Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
MUZZLELOADER BULLET SYSTEM
FIELD OF THE INVENTION
The present invention is directed to a bullet system suitable for
muzzleloaders that
improves the sealing of the bullet against the barrel during loading, and
improves loading and
shot accuracy. Specifically, the present invention is directed to a bullet
having a radially
deformable polymer component that may expand during seating or firing of the
bullet to engage
the barrel and to seal the bullet against the barrel and provide engravable
material engagable by
the rifling of the barrel.
BACKGROUND OF THE INVENTION
Muzzleloaders are a class of firearms in which the propellant charge and
bullet are
separately loaded into the barrel immediately prior to firing. Unlike modern
breech loaded
firearms where the bullet, propellant charge and primer are loaded as
prepackaged cartridges,
conventional muzzleloaders are loaded by feeding a propellant charge through
the muzzle of
the barrel before ramming a bullet down the barrel with a ramrod until the
bullet is seated against
the propellant charge at the breech end of the barrel. A primer is then fitted
to the exterior end
of a hole in the breech end of the barrel. The primer is then struck by an
internal inline firing
pin or an external hammer to ignite the propellant charge through the hole in
the breech end of
the barrel to create propellant gases for propelling the bullet.
The loading process of muzzleloaders creates issues unique to muzzleloaders.
Specifically, the muzzleloader loading process requires that, unlike
conventional breech loaded
firearms, the bullet travel through the barrel twice, once during loading and
once during firing.
The tight fit of the bullet to the barrel can create substantial friction as
the bullet travels through
the barrel and is etched by the barrel rifling. During firing, the expanding
propellant gases can
overcome the frictional forces to propel the bullet through the barrel.
However, during loading,
the user must overcome the frictional force by applying an axial force to the
bullet with the
ramrod until the bullet is seated against the propellant charge. The friction
between the bullet
and the barrel can complicate the determination as to whether the bullet has
been pushed far
enough down the barrel during loading and is properly seated against the
propellant charge. The
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relative position of the bullet to the propellant charge changes the
pressurization of the barrel
behind the bullet from the ignited propellant gases impacting the ballistic
performance and
potentially creating a substantial safety risk.
A recent trend in muzzleloading is placing an undersized bullet within a
polymer sabot
in a barrel sized for a larger caliber bullet. The undersized bullet body has
a higher muzzle
velocity than the larger caliber bullet providing improved ballistic
characteristics. The sabot is
sized to approximate the inner diameter of the barrel such that the sabot
tightly seals against the
barrel to efficiently propel the bullet and engage the rifling of the barrel
to impart spin to the
bullet. The sabot typically comprises a plurality of pedals or other unfurling
element that unfurl
from the bullet to separate the sabot from the bullet as the bullet leaves the
muzzle to disengage
from the bullet. While the sabot substantially improves the ballistic
performance of the
muzzleloader, the polymer sabot can be damaged or deformed by passing through
the barrel and
engaging the rifling twice. The deformation of the sabot or damage to the
sabot can cause the
sabot to release the bullet prematurely or impart a wobble to the bullet.
A similar concern with muzzleloaders is that the slower burning propellant
required by
muzzleloaders often foul the barrel with unconsumed residue requiring frequent
cleaning of the
barrel. The fouling often occurs so quickly that the barrel must be cleaned
after every shot. The
fouling can also interfere with the operation the sabot causing the sabot to
begin to unfurl from
the bullet prematurely within the barrel or break up within the barrel. In
addition to contributing
the fouling of the barrel, the deformation or damage to the sabot can impart
wobble into the
bullet or otherwise impact the ballistic performance of the bullet.
An additional complication is that the actual inner diameter of the barrel for
given caliber
can vary from manufacturer to manufacturer. A 50 caliber barrel can have an
actual inner
diameter ranging from 0.497 to 0.505 inches depending on the manufacturer.
Similarly, a 45
caliber bullet saboted for use in a 50 caliber barrel can have an outer
diameter varying from
0.450 to 0.452 inches, which in turn changes the outer diameter of the sabot
the bullet is seated
within. Although the variance is relatively small, the variance in tolerances
between the inner
diameter of the barrel and the outer diameter of the sabot can result in
substantially increased
friction between the cupped bullet and the barrel, which can cause the bullet
to become stuck
within the barrel during firing or loading. Similarly, an improper fit between
the barrel and an
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undersized sabot can create an inefficient seal between the sabot and the
barrel allowing gases
to escape around the bullet during firing. Accordingly, if the sabot-bullet
pairing is not properly
selected, the effectiveness of the muzzleloader can be substantially impacted.
A similar variability in muzzleloaders not present in cartridge based firearms
is the
variability of the size of the propellant charge. Unlike cartridge firearms
where a cartridge is
preloaded with a bullet and premeasured quantity of propellant is loaded into
the firearm for
firing, the bullet and propellant charge are combined within the firearm for
firing. Accordingly,
the muzzleloader operator can select the optimal bullet, propellant type and
quantity
combination for each shot, which is particularly advantageous given the long
reloading time for
.. muzzleloaders. While the variability of the bullet ¨ propellant charge
combination allows for an
optimized shot, varying the bullet and in particular the propellant and
quantity of propellant can
significantly change the appropriate seating depth of the bullet. With loose
or powdered
propellant such as black powder, the amount of propellant is often varied
between 80 and 120
volumetric grains. Similarly, propellants are often formed into cylindrical
pellets that are
stacked end-to-end within the barrel to form the propellant charges. The
pellets are typically
each about 1 cm in length and loaded in 1 to 3 pellet groups causing an even
greater variation
in the seating depth.
A common approach to determining whether a bullet has been properly seated
involves
marking the ramrod with a visual indicator that aligns with the muzzle of the
barrel when the
end of the ramrod is at the appropriate depth with the barrel. The visual
indicator is typically
marked by loading the propellant charge and ramming a test bullet through the
barrel. Once the
user is certain that the bullet is properly seated against the propellant
charge, the corresponding
portion of the ramrod at the muzzle is marked. Although this approach is
relatively easy to
implement and widely used, the visual indicator approach detracts from the
primary advantages
of muzzleloaders. As the visual indicator approach is set based on a
particular propellant charge
and bullet combination, a variation in the propellant charge that changes the
dimensions of the
propellant charge can render the visual indicator at best useless or at worse
a safety risk giving
a false appearance of a properly seated bullet.
As discussed above, the fouling can interfere with the safe operation of the
muzzleloader
as well as the ballistic performance of the bullet. While firing the
muzzleloader can be
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comparatively safer method of unloading the bullet, the muzzleloader must
often be cleaned
after each firing. In a hunting situation where the muzzleloader may be fired
several times to
unload the muzzleloader for transport, the barrel may require cleaning, which
can be difficult in
the field.
A current approach to addressing the reloading problem is replacing the closed
breech
end of the muzzleloader barrel with a screw-in, removable breech plug. The
breech plug is
removable from the breech end of the muzzle to remove the propellant charge
from behind the
bullet rather than attempting the remove the bullet from the muzzle end of the
barrel. While the
approach is effective in safely separating the propellant charge from the
bullet, a common
problem with removable breech plugs is seizing of the breech plug within the
barrel. The rapid
temperature changes during firing as well as the corrosive nature of many of
the propellants can
result in seizing of the corresponding threads of the breech plug and the
barrel. If not carefully
maintained, the breech plug will become difficult to remove to efficiently
unload the
muzzleloader.
A related concern is that the performance of the hygroscopic propellant itself
can be
easily and often detrimentally impacted by the environmental conditions in
which the propellant
is stored. The sensitivity of the propellant can often result in "hang fires"
where the ignition of
the propellant charge is delayed or the propellant charge fails to ignite
altogether. Hang fires are
frequent occurrences and create a substantial risk for the user. The
conventional approach to
dealing with a hang fire is to point the muzzleloader in a safe direction
until the muzzleloader
fires or until sufficient time has passed to reasonably assume that the
propellant charge failed to
ignite altogether. The unloading process through the muzzle of the
muzzleloader is particularly
dangerous in hang fire situations as the propellant charge may ignite during
the actual unloading
process. Similarly, unloading through a breech plug can similarly be dangerous
as the propellant
charge may ignite as the breech plug is removed.
Another safety concern unique to muzzleloaders is an undersized or oversized
propellant
charge. Unlike cartridge firearms where the amount of propellant loaded for
each shot is limited
by the internal volume of the cartridge, the amount of propellant loaded for
each shot in
muzzleloaders is only limited by the length of the barrel. While measures are
often used to
provide a constant quantity of propellant for each propellant charge, the
measures can be
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difficult to use in the field or in low light situation when hunting often
occurs. Similarly,
propellant can be formed into the pre-sized pellets that can be loaded one at
a time until the
appropriate amount of propellant is loaded. As with the measure, loading the
appropriate
number of pellets can be challenging in the field or in low light situations.
The fit between the barrel and bullet can impact the ballistic performance of
the
muzzleloader. However, tightly fitting the bullet to the barrel can make
properly seating of the
bullet against the propellant charge and determining the position of the
bullet within the barrel
during loading difficult. Accordingly, there is a need for efficiently loading
and seating a
muzzleloader bullet within the barrel while tightly fitting the bullet to the
walls and rifling of
the barrel.
SUMMARY OF THE INVENTION
A bullet system suitable for muzzleloaders, according to an embodiment of the
present
invention, can comprise a bullet body and a radially deforming polymer
component that expands
during seating of the bullet or firing of the bullet to seal the bullet
against the walls of the barrel.
The radial expansion of the polymer component also provides engravable
material that can be
engaged by the barrel rifling to impart spin to the bullet as the bullet
travels through the barrel.
In embodiments, bullet components are axially movable with respect to one
another to
effect a radial expansion, and/or provide a tactile indication of seating The
bullet system can
also comprise a seat force indicator tip insert that provides a tactile
sensation when the bullet is
properly seated against the propellant charge.
In one embodiment, the bullet can comprise a tail portion of a bullet body
postionable
within a well cavity defined by a radially deforming polymer cup. When used
herein "bullet"
includes a bullet body and components or accessories engaged therewith to be
discharged with
the bullet body, for example a cup engaged therewith. A "cup" typically has a
closed end and
an open axial end engaged with a portion of a bullet body. A cup can be
attached to the bullet
body, a "cupped bullet", so that is does not separate; the cup can be
separable after the bullet
leaves the barrel, such as a sabot; "cup" used herein includes "sabots". A
"bullet system" when
used herein, includes a plurality of bullet components, for example a bullet
body and the
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cooperating cup. It can also include associated components such as driving
bands, propellant,
a ramrod, and/or the firearm depending on the context.
In an embodiment, the tail portion can be moved axially within the well cavity
of the
cup between an axial extended position in which the tail portion partially
extends from the well
cavity and an axial retracted position in which the tail portion is fully
seated within the well
cavity. During loading, the tail portion of the bullet is positioned in the
axial extended position
as the bullet is fed into the muzzle and pushed down the barrel. In the axial
extended
configuration, the outer diameter of the cup approximates or is less than the
inner diameter of
the lands of the barrel rifling such that the cupped bullet can be pushed down
the barrel with a
ramrod with no or minimal engagement of the cup to the rifling. The minimal
engagement of
the cup allows the cupped bullet to be loaded with less friction between the
barrel and the bullet
such that user can determine tactilely when the bullet is seated against the
propellant charge.
Once the cupped bullet is seated, a continued axial force applied to the
cupped bullet
with the ramrod causes the tail portion to move into the retracted position
within the cup. The
cup can be generally deformable and comprise a deformable portion adapted to
expand radially
outward as the tail portion is pushed into the retracted position to seal the
cup against the barrel.
The radially expansion of the cup allows for an effective seal against the
barrel without having
to overcome the friction between the barrel and the bullet created when the
bullet is tightly fitted
to the inner diameter of the barrel. Accordingly, the radially expanding cup
can also reduce the
effect of manufacturer variances in barrel diameter on ballistic performance
as the radial
expansion of the cup effectively adapts the outer diameter of the cup to the
relative difference
in diameter between the initial outer diameter of the cup and the inner
diameter of the barrel.
The radially expanded portion of the cup can also provide engravable material
that can be
engaged by the rifling of the barrel to impart spin to the bullet as the
cupped bullet travels along
the barrel during firing.
In one aspect, the cup defines a reduced diameter portion within the well
cavity
engagable by the tail portion of the bullet as the tail portion is moved
axially from the axially
extended position into the axially retracted position. The cup can comprise a
deformable portion
at the reduced diameter portion such that the engagement of the tail portion
to the reduced
diameter portion causes the deformable portion to expand radially outward to
engage and seal
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against the barrel. In another aspect, the cup can comprise a quantity of
incompressible material
positioned within the well cavity between the tail portion and the closed end
of the well cavity.
As the bullet is pressed into the retracted position, the tail portion presses
against the
incompressible material causing the deformable portion of the cup at the
incompressible
material to expand radially outward. In one aspect, the cup can comprise
circumferential axial
scoring around the exterior of the cup at the deformable portion to control
the radial expansion
of the deformable portion. The scoring facilitates even radial expansion of
the deformable
portion of the cup.
In one aspect, the cup can further comprise a collar portion defining a second
reduced
diameter portion engaging the tail portion. In this configuration, the tail
portion can comprise a
notch positioned on the tail portion to engage the reduced diameter portion
when the tail portion
is positioned in the extended position. The notch maintains the bullet in the
extended position
as the cupped bullet is pushed down the barrel during loading. In one aspect,
the reduced friction
between the cupped bullet and the barrel allows the bullet to be pushed down
the barrel without
disengaging the second reduced diameter portion from the notch and pressing
the tail portion
into compressed position. Upon seating the cupped bullet against the
propellant, the cupped
bullet is braced against propellant such that sufficient axial force can be
applied to the bullet to
collapse the tail portion and radially expanding the cup.
In an embodiment, the bullet has a first axial length with a first maximum
radius, and a
.. shorter second axial length that corresponds to a second greater maximum
radius. By way of
engaged members with respective engaged annular surfaces and at least one of
the engaged
annular surfaces being a tapered surface, the bullet radially expands from the
first maximum
radius to the second greater maximum radius when the bullet is axially
compressed from the
first axial length to the shorter second axial length. The bullet has a
polymer outer surface
engravable by barrel rifling.
In an embodiment, the bullet has a first axial length and has an expandable
barrel
engagement portion with a first maximum radius, and the bullet having a
shorter second axial
length that corresponds to the expandable barrel engagement portion having a
second greater
maximum radius. By way of one surface of one member engaging a ramp (in cross
section) that
is, a tapered annular surface of another axially adjacent member, the bullet
radially expands
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from the first maximum radius to the second greater maximum radius when the
bullet is axially
compressed from the first axial length to the shorter second axial length. In
embodiments, the
expandable barrel engagement portion has a polymer outer surface engravable by
barrel rifling.
In an embodiment, the bullet has a first axial length and has a polymer barrel
engagement
portion with a first maximum radius, and a shorter second axial length that
corresponds to a
second greater maximum radius. By way of cooperating conical surfaces, the
bullet radially
expands by way of a radially expanding member from the first maximum radius to
the second
greater maximum radius when the bullet is axially compressed from the first
axial length to the
shorter second axial length.
In an embodiment, the bullet has a first axial length with a first maximum
radius, and a
shorter second axial length that corresponds to a second greater maximum
radius. The bullet is
loaded into a barrel at the first axial length with the first maximum radius
and when discharged
down the barrel is at a second shorter axial length and a second greater
maximum radius. By
way of cooperating frustoconical surfaces, the bullet radially expands from
the first maximum
radius to the second greater maximum radius when the bullet is axially
compressed from the
first axial length to the shorter second axial length. The bullet has a
polymer outer surface
engravable by barrel rifling.
In an embodiment, the bullet has a first axial length with a first maximum
radius, and a
shorter second axial length that corresponds to a second greater maximum
radius. By way of
means for radial expansion, the bullet radially expands from the first maximum
radius to the
second greater maximum radius when the bullet is axially compressed from the
first axial length
to the shorter second axial length.
In embodiments, the radially expanding member is a polymer and has a polymer
outer
surface engravable by barrel rifling that is part of the expanding member. In
an embodiment
the radially expanding member is a malleable and engravable metal, such as
lead, that has an
outer surface that is engravable. In embodiments, the radially expanding
member is fixed to,
that is, non-detachable, to a bullet body, forward of the radially expanding
member. In
embodiments, the radially expanding member is a cup and separates from a
bullet body after
the bullet body and cup leaves a barrel.
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A muzzleloader bullet system, according to an embodiment of the present
invention, can
comprise a bullet body and a polymer component having a radial cutting ring.
The radial cutting
ring cuts through barrel fouling buildup while the bullet is loaded into the
barrel, thereby
improving shot accuracy and reducing the force needed to load the bullet, and
reduce cleaning
in between shots. The radial cutting ring can be serrated and have a cutting
edge facing
rearwardly.
In an embodiment, the cup can further comprise a quantity of incompressible
material
positioned beneath the tail portion within the well cavity, wherein moving the
tail portion into
the retracted position presses the incompressible material radially outward to
deform the cup.
The incompressible material can be used in place or in addition to the reduced
diameter portion
to facilitate radial expansion of the cup. The incompressible material can be
a contained fluid.
In another embodiment, the bullet can comprise a bullet body defining a boat
tail and
further comprise a radially deforming polymer obturation skirt fitted to the
boat tail. The boat
tail provides a camming surface that radially spreads the obturation skirt as
the obturation skirt
is forced against the rear of the bullet during firing. Conventional
obturation skirts have a rear
facing cup portion to capture the expanding propellant gases from the ignited
propellant charges
such that the walls of the cup portion deform radially outward to obturate
against the barrel. The
camming surface of the boat tail of the present invention relies on the axial
force applied to the
obturation skirt by the propellant gases to facilitate radial expansion of the
obturation skirt. The
.. camming surface permits radial expansion of the obturation skirt without
relying on the difficult
to predict and often uneven radial deformation of the cup portion from the
expanding propellant
gases.
The obturation skirt covers the boat tail prior to firing to create a
conventional bullet
shape to improve the obturation of the obturation skirt to the barrel and the
engagement of the
obturation skirt to the rifling. Upon separation of the obturation skirt from
the bullet upon
leaving the barrel, the more aerodynamic boat tail of the bullet is exposed to
improve the overall
ballistic characteristics of the bullet. The separable obturation skirt
provides the obturation and
rifling engagement advantages of a conventional bullet shape during firing
while providing the
aerodynamic and ballistic advantages of a boat tailed bullet in flight.
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As with the cup, in an embodiment, the axial force for pressing the obturation
skirt
against the boat tail can be applied to the bullet by applying an axial force
to the bullet with a
ramrod to seat the obturation skirt against the propellant charge. The seating
force presses the
boat tail against the obturation skirt, which is braced against to the
propellant charge, to radially
expand the obturation skirt. In an embodiment, the obturation skirt can be
sized to approximate
the inner diameter of the rifling such that the bullet does not or minimally
engages the rifling.
In this configuration, the minimal contact between the rifling and the bullet
allows the user to
easily determine tactilly when the bullet is seated against the propellant
charge reducing the risk
that the bullet will not be properly seated against the propellant charges and
the associated risks.
In an embodiment, the bullet body can further comprise an axial well cavity
extending
through the boat tail and centered on the central longitudinal axis of the
bullet body.
Correspondingly, the obturation skirt can further comprise an axial post
insertable within the
well cavity to center the obturation skirt relative to the bullet body. The
axial post can maintain
the obturation skirt centered as the obturation skirt is pushed into the
camming surface to further
prevent uneven radial expansion of the obturation skirt. In an embodiment, the
axial post can
comprise at least one radial protrusion engageable to the walls of the well
cavity. In this
configuration, the well cavity can further comprise at least one detent
engageable by the
protrusion to fix the obturation skirt in at least one position.
In an embodiment, the axial post defines a lumen for conveying a quantity of
propellant
gas through the axial post into the well cavity. In this configuration, the
well cavity can further
comprise a pressure chamber at one end of the cavity for receiving the
propellant gases conveyed
by the lumen. During firing, the pressure chamber is pressurized as propellant
gases enter the
well cavity through the lumen. The propellant gases within the well cavity are
further
pressurized as the axial post moves axially forward as the obturation skirt is
pushed by the
expanding propellant as the bullet is propelled down the barrel during firing.
Upon exiting the
barrel, the ignited propellant gases behind the obturation skirt are
dissipated allowing the
pressurized gases within the pressure chamber to push the axial post axially
rearward to
disengage the obturation skirt from the bullet.
As shown in US Patent 6,782,830, similar problems exist with large smooth bore
weapons such as mortars. As with muzzleloaders, mortars travel through barrel
twice, once
CA 2828684 2018-10-25
during loading and once during firing. In an embodiment, an obturation skirt
according to an
embodiment of the present invention can be fitted to the boat tail of a mortar
round, wherein the
boat tail of the mortar round acts as a camming surface to facilitate radial
expansion of the boat
tail during firing.
In one embodiment, the bullet can comprise an undersized bullet body having an
overmolded polymer jacket having at least one polymer driving band expanding
circumferentially around the bullet body. The driving bands extend radially
outward to engage
the walls and rifling of the barrel to seal the bullet against the barrel and
impart spin to the bullet.
In an embodiment, the driving band can deform to seal against the barrel walls
during firing to
efficiently fire the bullet. In embodiments, the overmolded jacket does not
comprise petals or
other unwinding elements that can be damaged or deformed by fouling within the
barrel.
In an embodiment, the number and dimensions of the driving bands can be varied
to
increase or decrease the contact area between the polymer jacket and the
barrel, which increases
or decreases the friction between the polymer jacket and the rifling. In an
embodiment, the
polymer jacket can comprise a plurality of thin driving bands spaced along the
bullet body to
define a plurality of gaps between the driving bands. In this configuration,
the spaced driving
bands sufficiently engage the barrel walls and rifling to provide the
necessary seal and spin,
while reducing the overall contact area to reduce the friction between the
bullet and barrel. In
another aspect, the polymer jacket can comprise a single thick driving band
with a larger contact
area with the barrel walls and rifling. In this configuration, the larger
contact area permits a more
effective seal between the bullet and the barrel. As the driving bands are
molded, the number
and dimensions of the driving bands can be configured during manufacture
according to the
intended application of the bullet or the needs of the consumer.
In an embodiment, the polymer jacket can comprise at least one molded
ballistic element
that improves the ballistic or firing characteristics of the bullet. In an
embodiment, the molded
ballistic element can comprise an obturation skirt portion defining a rearward
facing cup portion
at the rear of the bullet to capture propellant gases generated by the ignited
propellant charge.
The cup portion is shaped to deform and expand radially outward as the
propellant gases contact
the obturation skirt, such that the obturation skirt engages the barrel to
seal the bullet to the
barrel. In another aspect, the ballistic element can comprise a molded boat
tail for reducing the
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drag of the jacketed bullet in flight, which improves the overall ballistic
characteristics of the
bullet. The boat tail of the polymer jacket can be molded onto a bullet body
with an existing
boat tail. Alternatively, the boat tail of the polymer jacket can be molded
over a conventional
cylindrical tail bullet to improve the ballistics of the conventional bullet.
In an embodiment, the bullet body can comprise a frustotapered head portion
and a
cylindrical tail portion. In this configuration, the bullet body can define an
axial well cavity
within the frustotapered head portion. The axial well cavity facilitates the
mushrooming of the
head portion of the bullet up on impact. In an embodiment, the jacketed bullet
can further
comprise a tip insert having a tapered head portion and an elongated tail
portion receivable
within the well cavity. The tapered head portion aligns with the frustotapered
head portion of
the bullet body when the tail portion is inserted into the well cavity to
improve the aerodynamic
characteristics of the jacketed bullet. In this configuration, the tip insert
and the polymer jacket
combine to encase the bullet body.
A bullet, according to an embodiment of the present invention, can comprise a
bullet
body and a radially deforming polymer component. In an embodiment, the
radially deforming
component can comprise a cup defining a well cavity. The bullet can further
comprise a
generally tapered head portion and a cylindrical tail portion, wherein the
tail portion is movable
within the well cavity in response to an axial force applied the bullet
between an extended
position in which the tail portion protrudes from the well cavity and a
retracted position in which
the tail portion is fully seated within the projectile. The cup can define a
reduced diameter
portion of the well cavity engageable by the tail portion as the tail portion
is pressed into the
retracted position. The cup can also define a deformable portion at the
reduced diameter portion
that expands radially outward as the tail portion engages the reduced diameter
portion to seal
the cupped bullet against the inner wall of barrel and engage the cup to the
rifling of the barrel.
In another aspect, the radially deforming component can comprise a polymer
obturation
skirt engageable to the rear of the bullet body. In this configuration, the
bullet body can further
comprise a tapered head portion and a boat tail. The boat tail is contoured to
provide a generally
frustoconical shaped tail portion of the bullet. The obturation skirt can
further comprise a cup
portion having at least one wall defining a cup cavity for receiving the boat
tail of the bullet. In
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an embodiment, the inner face of the wall can be angled to correspond to the
contour of the boat
tail.
In operation, the obturation skirt is movable axially relative to the boat
tail between a
pre-fired position and a fired position in which the obturation skirt is moved
forward axially
relative to the boat tail by the generated propellant gases. The forward
motion of obturation skirt
presses the walls of the cup portion against the boat tail, wherein the boat
tail acts as a camming
surface pressing the walls of the cup portion radially outward to engage the
walls and rifling of
the barrel. Alternatively, the obturation skirt can be braced against the
propellant charge during
loading. An axial force can be applied to the bullet with the ramrod to push
boat tail against
walls of the obturation skirt, which is braced against the propellant charge,
to force the walls
radially outward into engagement with the walls and rifling of the barrel.
In another aspect, the radially deforming component can comprise a polymer
jacket
having at least one molded driving band. The bullet body can further comprise
a generally
tapered head portion and a cylindrical tail portion. Each driving band extends
circumferentially
around the cylindrical tail portion. In an embodiment, the polymer jacket can
comprise a
plurality of driving bands spaced along the cylindrical tail portion to define
a plurality of gaps
between the driving bands. In another aspect, the polymer jacket can comprise
a single driving
band extending axially over the entire cylindrical tail portion of the bullet
body.
A method of loading a bullet into a muzzleloader, according to an embodiment
of the
present invention, comprises providing a bullet having a tail portion
positioned within a well
cavity of a cup, wherein the tail portion is moveable within the well cavity
between an extended
position and a retracted position. The method further comprises loading the
cupped bullet into
the muzzle of the barrel, wherein the cupped bullet is loaded with the tail
portion in the extended
position. The method also comprises applying an axial force to the cupped
bullet until the
cupped bullet is positioned in the breech end of the barrel. The method
further comprises
applying additional axial force to push the tail portion into the retracted
position within the well
cavity, wherein the tail portion engages the cup as the tail portion is pushed
into the retracted
position to cause radially expansion of a portion of the cup.
A method of manufacturing a jacketed bullet comprises providing a bullet body
having
a frustotapered head portion and a cylindrical tail portion. The method also
comprises inserting
13
CA 2828684 2018-10-25
a tail portion of a tip insert into the well cavity, wherein the tail portion
comprises a tapered
head portion that cooperates with frustotapered head portion to define a
generally conical body.
The method further comprises over-molding a polymer jacket onto the bullet
body, wherein the
tip insert and the polymer jacket cooperate to cover the exterior of the
bullet body. The method
can also comprise molding at least one driving band on the polymer jacket,
wherein the driving
band extends circumferentially around the cylindrical tail portion of the
bullet body. In an
embodiment, the method can further comprise molding at least one molded
element onto the
polymer body selected from the group of an obturation skirt, a boat tail, or
combinations thereof.
In an embodiment of the present invention, the bullet body comprises a tip
insert having
a tip tail portion receivable within an axial bullet well cavity. The tip tail
portion is loaded into
the barrel in an extended position in which the tip tail portion partially
extends from the bullet
well cavity. Upon seating against the propellant charge, an increased axial
force can be applied
to the tip insert to move the tail portion into a retracted position in which
the tail portion is fully
seated within the bullet well cavity. The movement of the tip tail portion
from the extended
position to the retracted position provides a tactile indication to the user
through the ramrod that
the bullet is properly seated against the propellant charge.
In an embodiment, the tip tail portion defines a circumferential protrusion
that engages
the edges of the bullet well cavity to maintain the tail portion in the
extended position as the
bullet is pushed down the barrel with the ramrod until the bullet is seated
against the propellant
charge. The circumferential protrusion is sized to prevent the tip tail
portion from moving into
the retracted position in response to the axial force applied to the tip
insert with the ramrod to
overcome the friction between the bullet and the barrel and move the bullet
through barrel. The
axial force as the bullet is pushed down the barrel is limited to the force
necessary to overcome
the friction between the bullet and the barrel. Upon seating of the bullet
against the propellant
charge, sufficient axial force can be applied with the ramrod to deform the
circumferential
protrusion and disengage the circumferential protrusion from the edge of the
well cavity
allowing the tip tail portion to move into the retracted position.
In an embodiment, the bullet can further comprise a collar portion at the
mouth of the
bullet defining a reduced diameter portion engageable to the tip tail portion
of the tip insert. In
this configuration, the tip tail portion defines a first notch positioned to
engage the reduced
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CA 2828684 2018-10-25
diameter portion when the tail portion is position in the extended position.
The engagement of
the reduced diameter portion to the first notch maintains the tip tail portion
in the extended
position until the bullet is seated against the propellant charge. In an
embodiment, the tip tail
portion can further comprise a second notch positioned to be engageable by the
reduce diameter
portion when the tip tail portion is moved into the retracted position so as
to maintain the tip tail
portion in the retracted position as the bullet travels down the barrel and in
flight.
In an embodiment, the tip insert can define a generally tapered head portion
that aligns
with the contours of the bullet exterior when the tail portion is moved into
the retracted position
to provide an aerodynamic shape for improved ballistic performance. In another
aspect, the tip
insert can comprise a rigid polymer or other frangible material adapted to
fracture upon impact
with the target. In this configuration, the bullet well cavity operates as a
hollow point tip
facilitating mushrooming of the bullet upon impact to increase the damage to
the target caused
by the bullet.
A bullet, according to an embodiment of the present invention, can define a
bullet well
cavity and comprise a tip insert having a tip tail portion. The tip tail
portion is movable within
the bullet well cavity between an extended position and a retracted position
in response to an
axial force applied to the tip insert. In an embodiment, the tip tail portion
further comprises a
circumferential protrusion positioned to engage the edge of the bullet well
cavity when the tip
tail portion is positioned in the extended position. In another aspect, the
bullet can further
comprise a collar portion at the mouth of the bullet well cavity having a
reduced diameter
portion engageable to the tail portion. In this configuration, tip tail
portion defines a notch
positioned to engage the reduced diameter portion when the tip tail portion is
positioned in the
extended position.
A bullet, according to an embodiment of the present invention, can comprise a
bullet
body having a tapered head portion defining a proximal end, a cylindrical tail
portion defining
a distal end and an outer body surface. The bullet body can further comprise a
first
circumferential outer groove positioned between the tapered head portion and
the cylindrical
tail portion. The bullet can comprise a deforming polymer component comprising
a first
polymer band extending circumferentially around the bullet body in the first
circumferential
outer groove, wherein a portion of the first polymer band extends radially
beyond the outer body
CA 2828684 2018-10-25
surface of the bullet body. In an aspect of the invention, the first polymer
band comprises an
elastomeric material. In another aspect, the first circumferential outer
groove is at the bourrelet
of the bullet body.
In a further aspect, the bullet body further comprises a second
circumferential outer
groove positioned between the tapered head portion and the cylindrical tail
portion. The
deforming polymer component can comprise a second polymer band extending
circumferentially around the bullet body in the second circumferential outer
groove, wherein a
portion of the second polymer band extends radially beyond the outer body
surface of the bullet
body.
In another aspect of the invention, the deforming polymer component comprises
a
polymer skirt extending circumferentially around the bullet body in the first
circumferential
outer groove, wherein a portion of the first polymer band extends radially
beyond the outer body
surface of the bullet body to an extent that a circumferential portion of the
polymer skirt may
extend distally along the outer surface of the bullet body. In an aspect, in a
resting state, the
circumferential portion of the polymer skirt extends distally along the outer
surface of the bullet
body past the distal end of the bullet body. In a further aspect, in a resting
state, the
circumferential portion of the polymer skirt extends distally along the outer
surface of the bullet
body to a point no further than a point proximal of the distal end of the
bullet body. In still a
further aspect, in its resting position, the polymer skirt is not form fitting
along its length to the
bullet body.
A method of loading a muzzleloader bullet, according to an embodiment of the
present
invention, comprises providing a bullet having a tip insert comprising a tip
tail portion movable
within a bullet well cavity defined by the bullet between an extended position
and a retracted
position. The method further comprises loading the bullet into the barrel of
the muzzleloader in
the extended position and applying an axial force to bullet to move the bullet
to the breech end
of the barrel, wherein the bullet defines a reduced diameter portion
engageable to the tip tail
portion to maintain the tail portion in the extended position as the bullet is
pushed down the
barrel. The method also comprises seating the bullet against a propellant
charge in the breech
end and applying an additional axial force to the tip insert to move the tip
tail portion into the
retracted position.
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CA 2828684 2018-10-25
In an embodiment of the invention, a bullet system comprising a metal bullet
body with
forward tip, a rearward end surface and a side surface, the side surface
having a circumferential
indentation, and a polymer cup secured to the side surface of the bullet body
at the
circumferential indentation, the cup having an open end defining a cup mouth
with a periphery,
the cup. In an embodiment the cup comprises a skirt portion that extends
axially rearward from
the circumferential indentation beyond the rearward end surface of the bullet
body and expands
radially outwardly under pressurization when fired from a fireami with a
propellant. In an
embodiment the skirt portion opens rearvvardly.
A bullet for muzzleloaders, according to an embodiment of the present
invention,
comprises a bullet body having a tapered head portion defining a proximal end,
a cylindrical tail
portion defining a distal end and an outer body surface. The bullet body
further comprises a first
circumferential outer groove positioned between the tapered head portion and
the cylindrical
tail portion. The bullet further comprises a deforming polymer component
comprising a first
polymer band extending circumferentially around the bullet body in the first
circumferential
outer groove, wherein a portion of the first polymer band extends radially
beyond the outer body
surface of the bullet body. In a further aspect, the bullet body further
comprises a second
circumferential outer groove positioned between the tapered head portion and
the cylindrical
tail portion; and the deforming polymer component comprises a second polymer
band extending
circumferentially around the bullet body in the second circumferential outer
groove, wherein a
portion of the second polymer band extends radially beyond the outer body
surface of the bullet
body.
In an embodiment, a bullet system comprising a bullet body and a polymer cup
engaged
therewith, the bullet body and engaged polymer cup having an axial expanded
position and axial
shortened position, the bullet having a forward tapered end and a rearward
tail portion, a cup
engaged with the rearward tail portion at a first position, the cup having a
radially deformable
portion that is positioned rearwardly of the increased radius portion of the
tail portion when the
bullet and engaged polymer cup are in the expanded position, whereby when the
cup is moved
forwardly on the bullet body to the shortened position, the radially
deformable portion moves
to the increased radius portion of the tail portion and radially deforms
outwardly.
Further embodiments are as follows:
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CA 2828684 2018-10-25
A projectile for a muzzleloader comprising a metal bullet body having a
tapered forward
end and a tail portion and a polymer component engaged therewith and being
coaxial therewith,
the metal bullet body and polymer annular component having cooperating axially
extending
surfaces where the component is axially shiftable with respect to the bullet
body whereby the
bullet has an axial elongated position and an axial shortened position.
The projectile above wherein the cooperating surfaces are annular and
concentric.
The projectile above wherein the component is configured as a cup with an open
end
and a closed end and the cup is attached to the tail portion of the bullet
body at a tapered portion,
whereby when the component shifts axially, a deformable portion of the cup
rides up the tapered
portion effecting a radial expansion of the component.
The projectile above wherein the component is radially inward from the bullet
body and
is engaged in central recess, the component having a pointed end defining the
forward point of
the bullet, the component seatable into the recess of the bullet body when
axially compressed
thereby axially shortening the projectile.
A projectile for a muzzleloader comprising a metal bullet body having a
tapered forward
end and a tail portion and a polymer component engaged therewith and being
coaxial therewith,
the metal bullet body and polymer annular component having cooperating axially
extending
surfaces where the component is axially shiftable with respect to the bullet
body presenting an
axially elongated position and an axially shortened position, and wherein at
the axially shortened
position the projectile has an increased radius compared to the axially
elongated position.
The projectile above wherein the projectile is insertable into the
muzzleloader in the
axially elongated position and wherein pressure from firing the muzzleloader
is sufficient to
shift the projectile to the axially shortened position.
The projectile above wherein the component comprises a rearwardly facing
circular
cutting edge sized for scraping the barrel of the muzzleloader when the
projectile is loaded into
the muzzleloader.
A projectile for a muzzleloader, the bullet system comprising a forward bullet
body and
a rearward polymer cup, the cup has a rearwardly facing cutting surface
extending around the
cup at a rearward end of the cup sized to scrape the barrel when loaded into
muzzle loader.
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CA 2828684 2018-10-25
A method of cleaning a muzzleloader and comprising scraping the barrel of the
muzzleloader by insertion of the projectiles above.
The above summary of the various representative embodiments of the invention
is not
intended to describe each illustrated embodiment or every implementation of
the invention.
Rather, the embodiments are chosen and described so that others skilled in the
art can appreciate
and understand the principles and practices of the invention. The figures in
the detailed
description that follow more particularly exemplify these embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be completely understood in consideration of the following
detailed
description of various embodiments of the invention in connection with the
accompanying
drawings, in which:
Figure 1 is a cross-sectional side view of a muzzleloader barrel for use with
the present
invention.
Figure 2 is a cross-sectional side view of a muzzleloader barrel with a
propellant charge
positioned at a breech end of the barrel and a conventional bullet positioned
at a muzzle end of
the barrel.
Figure 3 is a cross-sectional side view of the muzzleloader barrel depicted in
Figure 2,
with the conventional bullet pushed partially through the barrel with a
ramrod.
Figure 4 is a cross-sectional side view of the muzzleloader barrel depicted in
Figure 2
with the conventional bullet seated against the propellant charge in the
breech end of the barrel.
Figure 5 is a cross-sectional side view of a cupped bullet according to an
embodiment
of the present invention.
Figure 6 is a partial cross-sectional side view of a portion the cupped bullet
depicted in
Figure 5.
Figure 7 is a cross-sectional side view of a muzzleloader barrel with a
propellant charge
positioned at a breech end of the barrel and a cupped bullet, according to an
embodiment of the
present invention, positioned at a muzzle end of the barrel.
Figure 8 is a cross-sectional side view of the muzzleloader barrel depicted in
Figure 7,
with the cupped bullet pushed partially through the barrel with a ramrod.
19
CA 2828684 2018-10-25
Figure 9A is a cross-sectional side view of the muzzleloader barrel depicted
in Figure 7
with the cupped bullet seated against the propellant charge in the breech end
of the barrel and a
portion of the cupped bullet expanded radially outward to engage the rifling
of the barrel.
Figure 9B is a perspective view of a cupped bullet in the extended position
according to
an embodiment of the present invention.
Figure 9C is a perspective view of a cupped bullet in the retracted position
according to
an embodiment of the present invention.
Figure 9D is a perspective view of a cupped bullet in the retracted position
according to
an embodiment of the present invention.
Figure 9E is a rear perspective view of a bullet according to an embodiment of
the
present invention.
Figure 10 is a cross-sectional side view of a cupped bullet according to an
embodiment
of the present invention.
Figure 11A is a cross-sectional side view of a bullet body according to an
embodiment
of the present invention.
Figure 11B is an enlarged cross-sectional side view of a portion of the bullet
body
depicted in Figure 15.
Figure 11C is a rear view of the bullet body depicted in Figure 15.
Figure 11D is a front view of the bullet body depicted in Figure 15.
Figure 12A is an elevational view of a bullet in an expanded state.
Figure 12B is an elevational view of the bullet of FIG. 12A in the axial
shortened radially
enlarged state.
Figure 12C is a cross sectional view of a bullet in an axial expanded state.
Figure 13 is a perspective view of a cup sabot according to an embodiment of
the
invention.
Figure 14 is a side elevational view of the cup sabot of Figure 13.
Figure 15 is a cross-sectional view of the cup sabot of Figure 13 taken along
line A-A.
Figure 16 is a perspective view of a radial cutting ring according to an
embodiment of
the invention.
CA 2828684 2018-10-25
Figure 17A is a side elevational view of a cup sabot according to an
embodiment of the
invention.
Figure 17B is top perspective view of the cup sabot of Figure 17A.
Figure 17C is a perspective view of the cup sabot of Figure 17A.
Figure 18A is a cross-sectional view of a cup-bullet body combination having a
removable sabot, according to an embodiment of the invention;
Figure 18B is a cross-sectional view of a cup having a removable cutting ring,
according
to an embodiment of the invention.
Figure 19 is a perspective view of a cup having dual cutter rings, according
to an
embodiment of the invention.
Figure 20 is a side elevation view of the cup of Figure 22.
Figure 21 is a front perspective view of a bullet body according to an
embodiment of the
present invention.
Figure 22 is a rear perspective view of the bullet body depicted in Figure 21.
Figure 23 is a front perspective view of a bullet body and cup according to an
embodiment of the present invention.
Figure 24 is a rear perspective view of the bullet body and cup depicted in
Figure 21.
Figure 25 is a side cross-sectional side view of a bullet according to an
embodiment of
the present invention, wherein an obturation skirt of the bullet is positioned
in the pre-fired
position.
Figure 26 is a side cross-sectional side view of the bullet depicted in Figure
25, wherein
the obturation skirt is positioned in the post-fired position.
Figure 27 is a side cross-sectional side view of a bullet according to an
embodiment of
the present invention, wherein an obturation skirt of the bullet is positioned
in the pre-fired
position.
Figure 28 is a side cross-sectional side view of the bullet depicted in Figure
27, wherein
the obturation skirt is positioned in the post-fired position.
Figure 29 is a perspective view of a jacketed bullet according to an
embodiment of the
present invention.
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CA 2828684 2018-10-25
Figure 30 is a partial cross-sectional perspective view of the jacketed bullet
depicted in
Figure 29.
Figure 31 is a perspective view of a jacketed bullet according to an
embodiment of the
present invention.
Figure 32 is a partial cross-sectional perspective view of the jacketed bullet
depicted in
Figure 31.
Figure 33 is a cross-sectional side view of a bullet with a seat force
indicator tip insert
positioned in the extended position.
Figure 34 is a cross-sectional side view of the bullet depicted in Figure 33
with the seat
force indicator tip insert positioned in the retracted position.
Figure 35 is a cross-sectional side view of a bullet with a seat force
indicator tip insert
positioned in the extended position.
Figure 36 is a cross-sectional side view of the bullet depicted in Figure 35
with the seat
force indicator tip insert positioned in the retracted position
Figure 37 is a cross-sectional of bullet according to an embodiment of the
invention
where the skirt is formed of a malleable metal.
Figure 38 is a cross-sectional side view of a bullet with a seat force
indicator tip insert
positioned in the extended position with the tip formed of a non-polymer such
as a metal.
Figure 38A is a cross-sectional side view of a containment vessel according to
an
embodiment of the present invention.
Figure 39 is a side perspective view of a bullet according to an embodiment of
the
present invention, wherein an obturation band of the bullet is positioned in
the pre-fired position.
Figure 40 is a side sectional view of a portion of the bullet according to an
embodiment
of the present invention shown in Figure 39, wherein the obturation band of
the bullet is
removed.
Figure 41 is top plan view of a bullet according to an embodiment of the
present
invention with an obturation skirt.
Figure 42 is a cross-sectional side view along the longitudinal axis of a
bullet according
to an embodiment of the present invention, wherein an obturation skirt of the
bullet is positioned
in the pre-fired position.
22
CA 2828684 2018-10-25
Figure 43 is a cross-sectional side view along the longitudinal axis of a
bullet according
to an embodiment of the present invention, wherein an obturation skirt of the
bullet is positioned
in the pre-fired position.
Figure 44 is a sectional view of a portion of the bullet according to a
further embodiment
of the present invention shown in Figure 39, wherein the tail end of the
bullet is a boat tail.
Figure 45A is a sectional view of a portion the skirt of the bullet according
to a further
embodiment of the present invention shown in Figure 42, wherein an outer
surface of the skirt
of the bullet is knurled.
Figure 45B is a sectional view of a portion the skirt of the bullet according
to a further
embodiment of the present invention shown in Figure 42, wherein an outer
surface of the skirt
of the bullet is splined.
While the invention is amenable to various modifications and alternative
forms,
specifics thereof have been depicted by way of example in the drawings and
will be described
in detail. It should be understood, however, that the intention is not to
limit the invention to the
particular embodiments described. On the contrary, the intention is to cover
all modifications,
equivalents, and alternatives falling within the spirit and scope of the
invention as defined by
the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
As depicted in FIGS. 1A-5, a muzzleloader 20, for use with the present
invention,
generally comprises a barrel 22 having a muzzle 24, a breech end 26 with a
breech plug 27
therein. The barrel 22 can comprise smooth bore or a rifled bore 25 as
depicted in FIG. 1. As
depicted in FIGS. 2-4, the muzzleloader 20 may be conventionally loaded by
loading a
propellant charge 28 through the muzzle 24 of the barrel 22 and pushing the
propellant charge
28 toward the breech end 26 of the barrel 22. A projectile 29, with a bullet,
and a shiftable cup
34 on the tail of the bullet, according to the invention is positioned in the
muzzle 24 of the barrel
22 before being pushed down the barrel 22 with the ramrod until the bullet is
seated against the
propellant charge 28 As shown in FIG. 3. The muzzleloader is then ready to be
fired and the is
in an axially elongated state. FIG. 4 illustrates the muzzleloader after the
bullet has been fired,
the bullet in an axially retracted or compressed state and with an expanded
circumference.
23
CA 2828684 2018-10-25
Referring to FIGS. 5-12C, embodiments of bullets 30 according to the
invention, are
illustrated and generally comprise a bullet body 32 and a radially deforming
polymer component
configured as a cup 34. The bullet body 32 comprises a forward tapered end
configured as a
tapered head portion 36 and a generally cylindrical tail portion 38. The cup
34 defines a well
cavity 40 having a forward open end 42, a rearward closed end 44, a tubular
portion 41, and a
disc portion 43. The tail portion 32 of the bullet body is movable axially
within the open end 42
of the well cavity 40 between an axially elongated, extended, or expanded
position depicted in
FIGS. 5-8 and 9C-9D, in which a portion of the tail portion 38 is exposed at
the open end 42 of
the well cavity, and an axially shortened, retracted or collapsed position or
state as depicted in
.. FIGS. 9A, 9B and 13 in which the tail portion 38 is fully seated within the
cup 34. The tail
portion 38 is movable from the expanded or extended position into the
retracted position in
response, for example, by an axial force applied to the tip of the bullet body
32 with the ramrod
during loading. Alternately, the cup is movable from the expanded or extended
position to a
compressed or retracted position by a forced applied to the closed end 44 of
the cup when the
bullet is seated in the barrel and a propellant is discharged.
As best depicted in FIGS. 5, 6, 8, 10, in embodiments of the invention, the
cup 34 has a
inward lip a reduced diameter portion 46 at the closed end 44 of the well
cavity 40. As the tail
portion 38 is moved into the retracted or collapsed position, the tail portion
38 engages the
reduced diameter portion 46. In this configuration, the cup 34 comprises a
deformable portion
48 proximate to the reduced diameter portion 46, wherein engagement of the
tail portion 38 to
the reduced diameter portion 46 causes the deformable portion 48 to expand
radially outward to
engage the barrel. In an embodiment, the tail portion 38 further comprises a
foot portion 50
having an increased radial diameter to further increase the radial expansion
of the deformable
portion 48 as the tail portion 38 is moved into the axial shortened or
retracted position or state.
The tail portion 38 can define a plurality of axial grooves 52 in the foot
portion 50 defining
segments 53 that grip the cup for torque transmission from the cup as it
engages the rifling to
the bullet body.
In an embodiment, the cup 34 can comprise a polymer material including, but
not limited
to nylon, polyethylene and polypropylene. In certain aspects, the polymer
material can be
opaque or translucent. In another aspect, the polymer material can include a
friction reducing
24
CA 2828684 2018-10-25
additive or be formed of fluoropolymers. Generally the cup will be homogeneous
such that all
portions of the cup may be deformable, however, particular portions may have
structure, a thin
wall for example, or modifications, such as indentations or scoring, to
enhance the
deformability, particularly radial deformation. The cup is amenable to being
injection molded.
As depicted in FIGS. 12A-12B, in an embodiment, the cup 34 may comprise
circumferential axial scoring 54 on the exterior of the cup 34 at the
deformable portion 48 to
provide even radial expansion of the cup 34. The axial scoring 54 facilitates
even radial
expansion of the deformable portion 48 as the tail portion 38 engages the
reduced diameter
portion 46.
As depicted in FIG. 12C, in an embodiment of the present invention, the cup 34
can
comprise a disc 56 positioned at the closed end 44 of the well cavity 40. The
disc 56 comprises
incompressible material, that is, fixed volume material, such that moving the
tail portion 38 into
the retracted position applies an axial force to the disc 56 causing the disc
56 to expand radially
outward pushing against the deformable portion 48 of the cup 34, which in turn
causes the
deformable portion 48 to expand radially outward to engage the barrel 22. In
an embodiment,
the disc 56 used in conjunction with the reduced diameter portion 46 to
facilitate radial
expansion of the deformable portion 48.
The cupped bullet 30 is loaded by positioning the cupped bullet 30 in the
muzzle 24 of
the barrel 22 and pushing it or ramming it down the barrel 22 with the ramrod
until seated against
a propellant charge 28 in the breech end 26 of the barrel 22. In an
embodiment, the outer
diameter of the cup 34 approximates the inner diameter of the lands of the
barrel rifling such
that the cupped bullet 30 can be loaded down the barrel 22 with minimal
friction between the
bullet 30 and the barrel 22. Upon seating against the propellant charge 28, in
one embodiment,
continued axial force is applied to the cupped bullet 30 with the ramrod to
move the tail portion
32 into the retracted position and radially expanding the cup 34 to engage the
barrel 22.
As depicted in FIGS. 5-6 and 10, in one embodiment, the cup 34 further
comprises a
collar portion 58 defining a second reduced diameter portion 60 at the open
end 42 of the cup
34. In this configuration, the tail portion 38 defines a notch 62 engageable
by the second reduced
diameter portion 60 when the tail portion 38 is positioned in the extended
position. The
engagement of the notch 62 by the second reduced diameter portion 60 maintains
the tail portion
CA 2828684 2018-10-25
38 in the extended position as the cupped bullet 30 is pushed down the barrel
22 until the cupped
bullet 30 is seated against the propellant charge 28. The propellant charge 28
braces the cupped
bullet 30 permitting sufficient axial force to be applied to cupped bullet 30
to disengage the
second reduced diameter portion 60 from the notch 62. This can be by utilizing
a ram rod in
one instance and utilizing the force from the ignited propellant in another
instance. In an
embodiment, the notch 62 can have a increasing radius portion configured as a
sloped face 64
to facilitate disengagement of the second reduced diameter portion 60 and to
radially deform
the radially deformable cup. In another aspect, the collar portion 58 can
further comprise a
molded driving band 72 extending radially outward from the cup 34. The driving
band 72 is
adapted to engage the walls and rifling of the barrel 22 with the deformable
portion 58 to
maintain the axial alignment of the bullet 30 as the bullet 30 travels down
the barrel 22.
As depicted in FIGS. 9C-9D and 12A-12B, the cup 34 is shaped to follow the
contour
of the tapered head portion 36 of the bullet body 32 when the tail portion 38
is positioned in the
compressed or retracted position to eliminate or minimize gaps between the
open end 42 of the
cup 34 and the edge of the tapered head portion 36 of the bullet body 32. In
an embodiment, the
cup 34 is non-discarding such that the cup 34 travels with the bullet body 32
through its flight.
The smooth, gapless mating of the cup 34 and the tapered head portion 36
improves the
aerodynamic properties of the cupped bullet 30 in flight. As depicted in FIGS.
5-6 and 9E, in
this configuration, the tail portion 38 can define a annular or discrete tabs
65 that define second
notch 66 engagable by the second reduced diameter portion 60 when the tail
portion 38 is
positioned in the compressed or retracted position to maintain the cupped
bullet 30 in the
compressed or retracted position as the cupped bullet 30 leaves the muzzle 24
and in flight. As
depicted in FIG. 5, the tapered head portion 36 of the bullet body 32 can
further comprise score
lines 68 shaped to facilitate mushrooming of the tapered head portion 36 upon
impact with the
target. As depicted in FIGS. 11A and 1113, the tapered head portion 36 can
define an axial well
cavity 70 that opens upon impact to mushroom the tapered head portion 36 upon
impact with
the target.
A method of loading a cupped bullet 30 into a muzzleloader 22, according to an
embodiment of the present invention, comprises providing a bullet body 32
having a tail portion
38 positioned within a well cavity 40 of a cup 34, wherein the tail portion 38
is moveable within
26
CA 2828684 2018-10-25
the well cavity 40 between an extended position and a retracted position. The
method further
comprises loading the cupped bullet 30 into the muzzle 24 of the barrel 22,
wherein the cupped
bullet 30 is loaded with the tail portion 38 in the extended position. The
method also comprises
applying an axial force to the cupped bullet 30 until the cupped bullet 30 is
seated toward the
breech end 26 of the barrel 22. In one embodiment, the method further
comprises applying
additional axial force to push the tail portion 38 into the compressed or
retracted position within
the well cavity 40, wherein the tail portion 38 fully seats within the cup 34
as the tail portion 38
is pushed into the retracted position to cause radially expansion of a portion
of the cup 34. In
this embodiment, the bullet and cup are configured to resist compression until
about 10 pounds
.. of axial force is applied. In another embodiment, 20 pounds, in another
embodiment 5 pounds.
In another embodiment, the cup and bullet body are configured to preclude the
compression of
the cup and bullet body as the bullet is rammed into the barrel. In such
embodiment, the cup
and bullet body are configured to resist compression up to 300 pounds of axial
force. In another
embodiment, up to 250 pounds. In another embodiment, up to 350 pounds.
As depicted in FIGS. 7-9E, a bullet 30, according to an embodiment of the
present
invention, comprises a bullet body 32 and a radially deforming polymer
component comprising
a cup 34 having a radial cutting ring 36. The cup 34 can be made of injection
molded
polyethylene or other suitable polymers. The radial cutting ring 36 can be
insert molded or press
fit onto the cup 34, and can be made of copper, steel, or other metals, or
carbon fiber or other
suitable polymers, particularly polymers with fillers or surface coatings. The
converging tail
section 51 also includes ribs 56, which inhibit rotation between the cup 34
and bullet body.
As depicted in FIGS. 13-16, in an embodiment, cup 134 can include a toothed
radial
cutting ring 136. The toothed radial cutting ring 136 can include an annular
ring portion 158 and
a plurality of teeth 160 extending radially therefrom. The teeth 160 can
provide improved barrel
fouling removing capabilities in certain applications.
As depicted in FIGS. 13-15, in an embodiment, cup 234 can include a plurality
of petals
262 positioned to define the cup. As the bullet is fired, the petals 262 of
cup 234 are subjected
to a centrifugal force that causes the petals to open, thereby disengaging the
cup 234 from the
bullet.
27
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Referring to FIGS. 14A-14C, an embodiment of a cup configured as a base sabot
100 of
the claimed invention is depicted. Sabot 100 includes circumferentially
segmented body portion
102 and base portion 104.
Body portion 102 may comprise a polymer material such as those described
above, and
in an embodiment includes a plurality of segments or body extensions or petals
106 and main
body portion 108. The segments are separated by a plurality of body gaps 110.
Pedals 106 are connected to main body portion 108 and project axially away
from main
body portion 108. In an embodiment depicted, segmented body portion 102
includes four body
extensions 106 and defines four gaps 110. In other embodiments, more or fewer
extensions 106
and gaps 110 may be present.
Main body portion 108, in an embodiment, comprises a generally contiguous
annular
ring adjacent cutting ring 112 and body extensions 106. Main body portion 108
may be joined
to body extensions 106 in a variety of ways, including plastic welding,
adhesives, and so on. In
an embodiment, main body portion 108 and body extensions 106 are molded to
form an
integrated component.
In an embodiment, base portion 104 includes cutting ring 112 and splined
rearward end
portion 114. As described above, sabot cutting ring 112 may comprise a rigid
ring comprised
of a metal or other rigid material. Cutting ring 112 is affixed to rearward
end portion 114 and
main body portion 108. In an embodiment, cutting ring 112 defines a diameter
that is slightly
larger than a diameter of main body portion 108 and rearward end portion 114
so as to perform
a scraping, clearing, or cleaning function as it is delivered through the
barrel.
Rearward end portion 114 comprises a splined, disc-like structure affixed to
cutting ring
114. Rearward end portion 114 may comprise any of a variety of materials,
including plastics
or metal. In an embodiment, and as depicted, rearward end portion 114 defines
a plurality of
axially-extending channels 116 or splines distributed evenly about the
circumference of
rearward end portion 114.
In use, cutting ring 112 scrapes an inside surface of a muzzleloader barrel,
causing
material to build in the vicinity of rearward end portion 114. Channels 116
slow the
accumulation of material build-up in the region of rearward end portion 114
and cutting ring
112, such that sabot 100 may more easily be delivered through a muzzleloader
barrel.
28
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Referring to FIG. 18A, an embodiment of a cupped bullet 150 in cross section
is
depicted. Cupped bullet 150 includes projectile 152 and removable sabot 154.
Projectile 152 includes body portion 156 and tail portion 158. In an
embodiment, a
diameter of body portion 156 is greater than a diameter of a tail portion 158.
Tail portion 156
projects axially away from body portion 156, and may be coaxial with body
portion 156.
Removable sabot 154 includes body portion 164, cutting ring 166 and tail
portion 168.
Body portion 164 defines projectile receiving cavity 170 and cutting ring
cavity 172. Tail
portion 168 and cutting ring 166 are substantially similar to tail section 51
and cutting ring 36
as depicted in FIG. 6 and described in detail above.
When assembled tail portion 158 of projectile 152 is inserted into cavity 170
of sabot
154. In an embodiment, tail portion 158 fits tightly into cavity 170, but
remains removable
without by hand. In another embodiment, tail portion requires removal from
cavity 170 using
a hand tool. In either embodiment, projectile 152 remains removable or
separable from sabot
154.
This separability feature provides additional flexibility that may be
advantageous in the
field. In an embodiment, projectile 152 may be fired without sabot 154; in
another embodiment,
sabot 152 may be removably attached to sabot 154 and fired. Depending on the
shooter's needs,
projectile 152 may be used with and without sabot 154.
Referring to FIG. 18B, sabot 180 having optional cutting ring 182 is depicted.
In an
embodiment, sabot 180 includes body 184 with tapered tail portion 186. Tapered
tail portion
186 defines a tapered outer surface 188 and defines cutting-ring receiving
cavity 190.
Cutting ring 182 may be added to tapered tail portion 186 by axially aligning
cutting
ring 182 with tail portion 186 and forcing ring 182 over and along tapered
surface 188 until
cutting ring 182 seats in cutting ring receiving cavity 190. Once seated into
cavity 190, cutting
ring 182, in an embodiment, may not be removable.
In an embodiment, sabot 180 may be used with our without cutting ring 182. It
may be
desirable to attach cutting ring 182 to sabot 180 when using certain powders,
or when material
begins to build in a barrel. Under some circumstances, and as some might
perceive, it may not
always be desirable to use a cutting ring.
29
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Referring to FIGS. 19 and 20, an embodiment of sabot 200 having dual finger
rings 202a
and 202b is depicted.
In an embodiment, sabot 200 includes body portion 204, including a projectile
end 206
and tail end 208, and tail portion 210. Tail end 208 of body includes first
finger ring 202a and
second finger ring 202b.
Each finger ring 202 includes a plurality of fingers or tabs 212 equidistantly
spaced
about a circumference of tail end 208, and defining finger gaps 214. Fingers
212 project radially
outward from tail end 208 of body portion 204. In an embodiment, an outside
diameter of each
ring 202 is slightly larger than an outside diameter of body portion 204.
Finger ring 202a and
202b are separated by some distance, with finger ring 202a being closer to
tail portion 210 than
finger ring 202b.
Tail portion 210 extends axially away from body portion 204, and defines an
outside
diameter smaller than body portion 204. Tail portion 210 includes a plurality
of axially-
extending stabilizing ridges 216 distributed about a circumference of tail
portion 210.
When sabot 200 is inserted delivered through a muzzleloader barrel, fingers
212 contact
an inside surface of the muzzleloader barrel, and in some embodiments, flexing
slightly in an
axial direction. The contact of fingers 212 on the barrel causes material
accumulated on the
barrel inner surface to be removed. Gaps 214 between fingers 212 allow some
material to move
axially in the barrel, making it easier for sabot 200 to be moved through the
barrel. Further, the
use of a pair of rings 202a and 202b, rather than a single finger ring, also
increases the ease at
which sabot 200 may be delivered in the barrel due to material removed from
the barrel being
contained in the volume created between finger rings 202a and 202b, rather
than having that
material build up behind sabot 200 and interfere with the travel of sabot
200..
Referring again to FIGS. 2-4, a method of loading a cupped bullet 30 into a
muzzleloader
22, according to an embodiment of the present invention, comprises providing a
bullet body 32
having a tail portion 40 positioned within a well cavity 42 of a cup 34,
wherein the tail portion
40 is moveable within the well cavity 42 between an extended position and a
retracted position.
The method further comprises loading the cupped bullet 30 into the muzzle 24
of the barrel 22,
wherein the cupped bullet 30 is loaded with the tail portion 40 in the
extended position. As the
cupped bullet 30 is pushed down the barrel, radial cutting ring 36 cuts
through fouling that has
CA 2828684 2018-10-25
built up inside barrel 22, pushing the barrel fouling around converging tail
section 51. The
method also comprises applying an axial force to the cupped bullet 30 until
the cupped bullet
30 is positioned in the breech end 26 of the barrel 22. The method further
comprises applying
additional axial force to push the tail portion 40 into the retracted position
within the well cavity
42, wherein the tail portion 40 engages the cup 34 as the tail portion 40 is
pushed into the
retracted position to cause radially expansion of a portion of the cup 34,
thereby engaging the
rifling of barrel 22.
As depicted in FIGS. 21-24, a bullet 130, according to an embodiment of the
present
invention, comprises a bullet body 132 and a radially deforming polymer
component comprising
a cup with an axial post 148. The cup is configured as an obturation skirt
134. The bullet body
132 further comprises a generally tapered head portion 136 and a boat tail
138. The boat tail 138
defines an angled camming surface 140. The obturation skirt 134 further
comprises at least one
wall 142 defining a cup for receiving the boat tail 138 of the bullet body
132. The wall 142 is
angled to follow the angle of the camming surface 140. In an embodiment, the
obturation skirt
34 can comprise a single circumferential wall 142 encircling the cup as
depicted in FIGS. 25-
28. In another aspect, the obturation skirt 134 can further comprise a
plurality of petals 140
positioned to define the cup.
During loading, seating the bullet 130 against the propellant charge 28 pushes
the walls
142 of the obturation skirt 134 against the camming surface 140, which is
angled to deform the
walls 142 radially outward to engage the barrel 22 and the rifling.
Alternatively, during firing,
the expanding propellant gases push against the obturation skirt 134 against
the camming
surface 140 of the bullet body 132 to radially expand the obturation skirt
134. In an embodiment,
the obturation skirt 134 can comprise a second cup portion 144 is positioned
at the rear of the
bullet 130 opposite the cup defined by the wall 142. The second cup portion
144 is shaped to
capture the propellant gases and facilitate efficient launch of the bullet
130.
As depicted in FIGS. 25-28, in an embodiment, the bullet body 132 can define
an axial
well cavity 146 aligned with the central longitudinal axis a-a of the bullet
body 132. The
obturation skirt 134 further comprises an axial post 148 insertable into the
well cavity 146. The
axial post 148 maintains the correct alignment of the obturation skirt 134 to
the bullet body 132
as the wall 142 is pressed against the camming surface 140 and deformed
radially outward.
31
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In an embodiment, the well cavity 146 defines an enlarged pressure chamber 150
at one
end of the well cavity 146. In this configuration, the axial post 148 defines
a lumen 152 for
conveying propellant gases into the pressure chamber 150. During firing, the
pressure chamber
150 is pressurized by the propellant gases. The main body of propellant gases
behind the
obturation skirt 134 maintains the obturation skirt 134 against the camming
surface 140 as the
bullet 130 travels down the barrel 22. Upon leaving the barrel 22, the main
body of propellant
gases dissipates allowing the pressurized pressure chamber 150 to push against
the axial post
148 and separate the obturation skirt 134 from the bullet body 132.
As depicted in FIGS. 29-32, a cupped bullet 230, according to an embodiment of
the
present invention, comprises a bullet body 232 and a polymer jacket 234. The
bullet body 232
further comprises a tapered head portion 236 and a cylindrical tail portion
238. In an
embodiment, the bullet body 232 can comprise a metal or metal composite
including, but not
limited to lead, steel, tungsten or other conventional bullet materials. The
polymer jacket 234
further comprises at least one molded driving band 240 extending
circumferentially around the
cylindrical tail portion 38. In an embodiment, the polymer jacket 234 can
comprise a plurality
of driving bands 240 spaced along the cylindrical tail portion 238 as depicted
in FIGS. 29-30.
The driving bands 240 are spaced along the cylindrical tail portion 38 to
maintain sufficient
contact with the barrel 22 to maintain the alignment of the bullet body 232
within the barrel 22
and seal the bullet 230 to the barrel 22. In another aspect, the polymer
jacket 234 can comprise
a single driving band 240 extending axially to encompass a substantial portion
of the tail portion
238 as depicted in FIGS. 31-32.
As depicted in FIGS. 29-32, in an embodiment, the polymer jacket 234 further
comprises at least one molded ballistic element. As depicted in FIG. 30, the
molded element can
comprise a molded boat tail 242 at the rear of the bullet 230. The molded boat
tail 242 reduces
the drag caused by the cylindrical tail portion 238 of the bullet 230. As
depicted in FIG. 326,
the molded element can comprise an obturation skirt portion 244 at the rear of
the bullet 230.
The obturation skirt 244 further comprises a cup portion 246 oriented rearward
from the
cylindrical tail portion 238 of the bullet body 232 to capture propellant
gases from the propellant
charge 28. The cup portion 246 expands radially during firing to seal the
bullet 230 against the
barrel 22.
32
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As depicted in FIG. 29-32, in an embodiment, the bullet body 232 can further
comprise
an axial well cavity 46. In this configuration, the bullet body 232 defines a
frustotapered head
portion 248. The well cavity 246 facilitates the mushrooming of the head
portion 248 upon
impact with the target. In an embodiment, the bullet 230 can further comprise
a tip insert 50
having a tapered head portion 252 and a tail portion 254 insertable into the
well cavity 246. The
tapered head portion 252 is shaped to align with the frustotapered head
portion 248 when the
tail portion 254 is inserted into the well cavity 246.
A method of manufacturing a jacketed bullet 230 comprises providing a bullet
body 232
having a frustotapered head portion 248 and a cylindrical tail portion 238,
wherein the bullet
body 232 defines an axial well cavity 254. The method also comprises inserting
a tail portion
254 of a tip insert 50 into the well cavity 246, wherein the tip insert 250
comprises a tapered
head portion 252 that aligns with frustotapered head portion 248 to provide an
aerodynamic
body. The method further comprises over-molding a polymer jacket 234 onto the
bullet body
232, wherein the tip insert 250 and the polymer jacket 234 cooperate to cover
the exterior of the
bullet body 32. The method can also comprise molding at least one driving band
240 on the
portion of the polymer jacket 234 encompassing the cylindrical tail portion
238 of the bullet
body 232. In an embodiment, the method can further comprise molding at least
one molded
element onto the polymer body 234 selected from the group of an obturation
skirt 244, a boat
tail 242, or combinations thereof.
As depicted in FIGS. 33-36, a tipped bullet 330, according to an embodiment of
the
present invention, comprises a bullet body 332 defining an axial bullet well
cavity 334. The
axial bullet well cavity 334 further comprises a mouth 336 defining an opening
into the axial
bullet well cavity 334. The tipped bullet 330 also comprises a tip insert 338
having a tapered
head portion 340 and a generally cylindrical tip tail portion 342 insertable
into the mouth 336
of the bullet well cavity 334. The tip tail portion 342 is moveable between an
extended position,
depicted in FIGS. 31 and 33, in which a portion of the tip tail portion 342
protrudes from the
mouth 336 of the bullet well cavity 334 and a retracted position, depicted in
FIGS. 32 and 34,
in which the tip tail portion 342 is fully seated within the bullet well
cavity 334.
As depicted in FIGS. 33 and 34, in an embodiment, the bullet 330 can define a
collar
portion 344 at the mouth 336 of the bullet well cavity 334. The collar portion
344 further
33
CA 2828684 2018-10-25
comprises at least one collar protrusion 346 extending radially inward to
engage the tip tail
portion 342. In an embodiment, the collar protrusion 346 comprises a reduced
diameter portion
extending around the entire circumference of the mouth 36 of the bullet well
cavity 334. The tip
tail portion 342 further comprises a first groove 348 positioned to engage the
collar protrusion
346 when the tail portion 42 is positioned in the extended position as
depicted in FIG. 33. The
engagement of the collar protrusion 346 to the first groove 348 maintains the
tip tail portion 342
in the extended position until an axial force exceeding a predetermined
threshold is applied to
the tip insert 338, which disengages the collar protrusion 346 from the first
groove 348. In an
embodiment, the tip tail portion 342 further comprises a second groove 348
positioned to engage
the collar protrusion 346 when the tip tail portion 342 is positioned in the
retracted position as
depicted in FIG. 34.
As depicted in FIGS. 35-36, in an embodiment, the tip tail portion 342 can
further
comprise a tail protrusion 350 that extends radially outward. The tail
protrusion 350 is
positioned to engage the mouth 336 of the bullet well cavity 334 when the tip
tail portion 342
is positioned in the extended position, as depicted in FIG. 33, to maintain
the tip tail portion 342
in the extended position until an axial force exceeding a predetermined
threshold is applied to
the tip insert 338. If an axial force exceeding the predetermined threshold is
applied to the tip
insert 338 the tail protrusion 350 deforms allowing the tip tail portion 342
to move into the
retracted position.
As depicted in FIGS. 29-34, in operation, the tipped bullet 330 is loaded into
the muzzle
24 of the barrel 22 with the tip insert 338 positioned in the extended
position. An axial force is
applied to the tipped bullet 330 with the ramrod to overcome the friction
between the bullet 330
and the barrel 22 to allow the bullet 330 to slide down the barrel 22. The
predetermined axial
force threshold is greater than the axial force necessary to overcome the
friction between the
bullet 330 and the barrel 22. As the bullet 330 is being pushed down the
barrel 22, the axial
force applied to the bullet 330 cannot exceed the force necessary to overcome
the friction
between the bullet 330 and the barrel 22. Upon seating of the bullet 330
against the propellant
charge 28 at the breech end of the 26 of the barrel 22, sufficient axial force
can be applied to the
tip insert 338 to exceed the axial force threshold and move the tip insert 338
into the retracted
position. The movement of the tip insert 338 into the retracted position
provides a tactile
34
CA 2828684 2018-10-25
sensation through the ramrod to the user that seating force has exceeded the
necessary threshold
to properly seat the bullet 330 against the propellant charge 28.
A method of loading a tipped bullet 330, according to an embodiment of the
present
invention, comprises providing a bullet 330 and a tip insert 338 having a tip
tail portion 342
movable within a bullet well cavity 334 defined by the bullet 330 between an
extended position
and a retracted position. The method further comprises loading the bullet 330
into the barrel 22
of the muzzleloader 20 in the extended position and applying an axial force to
bullet 330 with a
ramrod to move the bullet 330 to the breech end 26 of the barrel 22, wherein
the bullet 330
defines a reduced diameter portion engageable to the tip tail portion 342 to
maintain the tip tail
portion 342 in the extended position as the bullet is pushed down the barrel.
The method also
comprises seating the bullet 330 against a propellant charge 28 in the breech
end 26 and applying
an additional axial force with the ramrod to the tip insert 338 to move the
tip tail portion 342
into the retracted position.
As depicted in FIGS. 39-41, a bullet 830, according to an embodiment of the
present
invention, comprises a bullet body 832 and a deforming polymer component
comprising one or
more obturation polymer bands 840 extending circumferentially around the
bullet body 832.
The bullet body 132 further comprises a generally tapered head portion 836 and
a cylindrical
tail 838. In another aspect of the invention, the cylindrical tail 838 is a
boat tail 839 shaped, as
shown in FIG. 44.
The obturation bands 840 comprise an elastomeric material which form fits
within a
circumferential groove 841 in the bullet body 832. The groove is best seen in
FIG. 40, which is
a side sectional view of a portion of the bullet 830 according to an
embodiment of the present
invention shown in Figure 39, wherein the obturation band 840 of the bullet is
removed. An
obturation band 840 of the invention may be elastomeric such that it conforms
to and constricts
.. the groove 841 of the bullet body 832.
In an embodiment, as seen in FIG. 41, the bullet body 832 comprises more than
one
groove 841 with more than one obturation band 840. The band(s) 840 are
positioned along the
bullet body 832 to optimize obturation. As such, in some aspects of the
invention, the bands 840
and grooves 841 are position at the widest portions or bourrelet of the bullet
body 832. In other
aspects, the bands 840 and accompanying grooves 841 are positioned at narrower
portions of
CA 2828684 2018-10-25
the bullet body 832. In this case, the bands' radial thickness is greater to
accommodate the
greater distance to the inside surface of the barrel 22.
The driving bands 840 are spaced along the cylindrical tail portion 838 to
maintain
sufficient contact with the barrel 22 to maintain the alignment of the bullet
body 832 within the
barrel 22 and seal the bullet 830 to the barrel 22.
In another aspect, as shown in FIGS. 42 and 43, the radial thickness of the
obturation
band is increased to form an obturation skirt 844. As seen in FIG. 42, the
obturation skirt may
extend downward along the bullet body 832 and past the bullet tail end 838. In
some aspects of
the invention, the obturation skirt 844 is not form fitting along its length
to the bullet body 832.
The skirt 844 includes portions radially beyond the point of engagement
between the skirt 844
and the bullet body 832 that have greater resting inner diameters than the
outer diameter of the
bullet body 832 when the skirt 844 is wrapped around the tail end 838 of the
bullet body 832.
In a further aspect of the invention, the skirt 844 extends down around the
bullet body 832 and
terminates short of the terminating end 839 of the bullet tail end 838.
During firing, the expanding propellant gases push against the underside of
the
obturation skirt 844, expanding the skirt 844 radially against the inner
surface of the barrel 22
to seal the bullet 830 against the barrel 22.
A method of manufacturing a bullet 830 comprises providing a bullet body 832
having
a frustotapered head portion 836, a cylindrical tail portion 838 and a
circumferential groove 841
radially around the bulled body 832. The method also comprises inserting a
polymer band 840
into the groove 841. The method further comprises providing the bullet body
832 with a plurality
of grooves 841 and a plurality of corresponding polymer bands 841 and
inserting one of the
bands 841 into each groove 841.
A further method of manufacturing a bullet 830 comprises providing a bullet
body 832
having a frustotapered head portion 836, a cylindrical tail portion 838 and a
circumferential
groove 841 radially around the bulled body 832. The method also comprises
inserting a polymer
skirt 844 into the groove 841. In an aspect of the method, the skirt 844
extends down the bullet
body 832 and past the tail portion 838. In another aspect, the skirt extends
down the bullet body
short of the terminating end of the tail portion 838.
36
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According to further aspects of the invention, the skirt 844 is knurled 846 as
shown in
FIG. 45A (showing a sectional portion of a skirt at the skirt's terminating
end 845) or splined as
shown in FIG. 45B (showing a sectional portion of a skirt at the skirt's
terminating end 845) to
create an interface with the barrel 22 to encourage rotational lock-up.
The projectile, in use, rides on the lands of the rifled barrel 22 and the
polymer
band(s)/skirt 840/844, which extend from the groove(s) 841 of the bullet body
832, fill and seal
the grooves of the rifled barrel preventing propellant gas leakage. The
grooves 841 and
band(s)/skirt 840/844 are physically dimensioned and formed to ensure
mechanical integrity is
maintained. Better transmission of spin to the projectile provides better
dynamic stability and
results in better accuracy. Locating the polymer on the bourrelet of the
projectile with a reduced
length allows for lower insertion force (ease of loading) as well as improved
filling of the rifling
grooves (obturation). Energy generated by the propellant is better transmitted
to the projectile
and not allowed to bleed past the bullet.
According to further aspects of the invention, the bands/skirts 840/844 are
elastomeric
and removable allowing for installation of specific diameter bands by the end
user. This user
modification allows for projectile customization/optimization to a specific
rifle thereby
accommodating any of the bore diameter variations which are common to the
industry. In
further aspects of the invention, there is provided consumer kits with bands/
skirts 840/844 of
several different diameters for end user customization of the projectile
configuration.
Suitable materials for the bands 840 and skirt 844, include, but are not
limited to,
polymer material comprising nylon, polyethylene, polypropylene and suitable
elastomeric
materials. In certain aspects, the polymer material can be opaque or
translucent. In another
aspect, the polymer material can include a friction reducing additive or be
formed of
fluoropolymers.
According to aspects of the invention, the bullet body 832 may comprises lead,
aluminum, any suitable metallic and lead-free material, a metallic/polymer
composition or a
polymer based material. In some aspects, the bullet body may be jacketed with
suitable
materials, including copper and any other suitable jacket material. If the
bullet body comprises
a polymer material, the bands/skirt 840/844 may form a materially integrated
part of the bullet
body 832.
37
CA 2828684 2018-10-25
While the invention is amenable to various modifications and alternative
forms,
specifics thereof have been depicted by way of example in the drawings and
described in detail.
It is understood, however, that the intention is not to limit the invention to
the particular
embodiments described. On the contrary, the intention is to cover all
modifications, equivalents,
and alternatives falling within the spirit and scope of the invention as
defined by the appended
claims. All of the features disclosed in this specification, and/or all of the
steps of any method
or process so disclosed, may be combined in any combination, except
combinations where at
least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification may be replaced by alternative
features
serving the same, equivalent or similar purpose, unless expressly stated
otherwise. Thus, unless
expressly stated otherwise, each feature disclosed is one example only of a
generic series of
equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment
(s). The
invention extends to any novel one, or any novel combination, of the features
disclosed in this
specification, or to any novel one, or any novel combination, of the steps of
any method or
process so disclosed
Although specific examples have been illustrated and described herein, it will
be
appreciated by those of ordinary skill in the art that any arrangement
calculated to achieve the
same purpose could be substituted for the specific examples shown. This
application is intended
to cover adaptations or variations of the present subject matter. Therefore,
it is intended that the
invention be defined by the attached claims and their legal equivalents, as
well as the following
illustrative aspects. The above described aspects embodiments of the invention
are merely
descriptive of its principles and are not to be considered limiting. Further
modifications of the
invention herein disclosed will occur to those skilled in the respective arts
and all such
modifications are deemed to be within the scope of the invention.
38
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