Note: Descriptions are shown in the official language in which they were submitted.
1~673~3
COMPENSATOR FOR MUZ ZLE CLIMB
This invention relates to guns and, in particular
to lift compensators or stabilizers for guns, especially
automatic rifles, machine guns, and the like.
It is well known that the muzzle climb or lift when a
gun is fired results from the reaction of the recoil against
the support for the gun. The amount of lift is proportional
to the recoil and the direction is determined by the manner
in which the gun is supported, as for example by the body
and arms of the person firing the gun. A right or left hand-
ed marksman holding a rifle in a typical right or left hand-
ed firing position respectively, will experience a rightward
or leftward muzzle lift, respectively, at approximately 45
to the vertical, whereas a gun typically supported on a bi-
pod where the lateral forces are balanced will exhibit a ver-
tical lift.
Muzzle brakes have been provided to reduce cecoil and
thereby ~o reduce muzzle lift, especially for larger guns,
but such devices also dissipate much of the power that could
otherwise be used to discharge the bullet and are distin-
guishable in operation from compensators which attempt to
create a transverse force against the gun barrel in opposi-
tion to the direction of the muzzle climb, rather than to
create an axial force on the barrel in opposition to the re-
coil.
An important object o the present invention is toprovide an improved compensator or guns that is adjustably
and detachably mountable on the muzzle brake, flash hider or
I ~ ~73~3 ' .
--2--
flash suppressor of the g~n barrel
adjacent the muzzle having ~ number of circumferentially
spaced ports (referred to herein as flash hider ports) that
- are effective in reducing the visibility or flash of the
S gases discharged from the barrel.
The flash hider ports are provided in a slightly en-
larged diameter bore portion of the barrel at the muzzle
end, which portion may be considered herein as an expansion
chamber and part of the barrel, even though it is usually
detachable from the gun to facilitate cleaning for example.
The flash hider ports extend generally radially through
the barrel. Accordingly, when the gun is fired, gases flow-
ing axially along the barrel enter the expansion chamber
where a portion of their heat energy is converted to kinetic
lS energy. Some of the gases are then discharged transversely
of the barrel to the atmosphere. Although such ports are ef-
fective in reducing flash and in some instances are designed
to reduce recoil and to compensate for muzzle climb, they do
not by themselves serve effectively as a compensator because
in order to be effective as a flash hider, much of the
transversely discharged gas either has no effect in opposing
muzzle lift, or actually increases the lift. I~here the
flash hider ports are designed to be more effective as a
compensator,the flash hiding function is seriously impaired,
as for example in accordance with the device shown in U.S.
patent to Ellis et al, No. 3,971,2~5, where only two flash
hider ports are available for use.
Other important objects of the present invention are
thus to provide an improved compensator of the type de-
scribed which is rotatably adjustable on a typical effectiveflash hider; which utilizes the gases that have already hcen
expanded in the expansion chamber of the flash hider and
have already been discharged transversely of the barrel via
the flash hider ports; which comprises deflector means
external to the flash hider or redirecting the transverse
ga-s flow from one or more of the flash hider ports to oppose
the muzzle lift effectively; which may be readily adapted
for rotatable adjustment on most flash hiders now in use;
' :
I ~ 673~)3
and which has circumferentially spaced gas control portions
selectively positionable with respect to the flash hider
ports by the rotational adjustment for redirecting
transversely discharged gases from the ports in
predetermined transverse directions to compensate for left or
right handed or vertical muzzle climb or lift, as determined
by the adjustment.
By virtue of the present invention, some of the trans-
versely discharged gases from the flash hider ports that
would otherwise be ineffective in opposing muzzle lift, or
might even enhance muzzle lift, are redirected to effect a
reaction force opposing the muzzle lift. Furthermore, the
energy of such gases that is now used in accordance with the
present invention to oppose muzzle lift is extracted from
the heat energy of the gases to reduce their tem~erature and
accordingly their visible flash, resulting in minimum
impairment of the flash hiding function. Also in contrast
to the above mentioned Ellis et al compensator which can
only use flash hider ports located above the horizontal
axial plane of the gun barrel, the concept of the present
invention as described below obtains effective compensation
for muzzle lift from flash hider ports located at any circum-
ferential position on the gun barrel. i~ost military rifles
are equipped with flash hiders having circular cylindrical
surfaces to accommodate grenade launching therefrom without
concern for the angular position of the grenade on the flash
hider. Accordingly the soldier in the field may readily
adapt his gun to obtain effective compensation for muzzle
lift merely by attaching the compensator described herein
and rotatably adjusting the same to a desired position to
accommodate his particular style of shooting, and in
particular to compensate for either left or right hand use
or bipod mounting, for example.
l_ 1 167303 '`
According to the invention the compensator may h~ve a
axially slotted portion fitting around the muzzle end of a
gun ba~rel and the locating me~ns for securing the element
on the barrel may comprise a clip for ti~htening tlle slotted
portion so that it clamps the gun barrel. Alternatively,
the locating means may comprise a stop carried by the
compensator for engaging.a notch in the periphery of the
barrel. The stop may be resiliently biased to engage the
notch and may be retr~ctable against the resilient biasing.
More specifically, the compensator may compcise a tubu-
lar element dimensioned to fit coaxially on the ~uzzle end
of a gun barrel at the region of the flash hider and having
at least one compensating vent means disposed or adapted to
direct combustion gases discharged transversely from ~he
flash hider ports primarily to one side of the barrel. The
locating means for securing the element on the barrel may
comprise a stop mounted on the element for passing there-
through and engaging in a flash hider port. The stop ~ay be
mounted on a lever for movement to and from a securing por-
tion within the port.
BRIEF DESCRIPTION OF THE SCHEMATIC DRAWINGS
Figure 1 is a side elevation o a compensator
mounted on a flash hider at the muzzle end of a gun
barrel
Figure 2 is a transverse sectional view through
the flash hider and compensator of Figure 1, looking
leftward, the compensator being adjusted for use by a
right-handed rifleman, the muzzle end of the rifled
portion of the gun barrel being shown in phantom.
Figure 3 is a view of the compensator removed
from the gun, looking in the direction of arrow 3
of Figure 2.
Figure 4 is a fragmentary ~ection through part of the
compensator and part of the flash hider at the region
of the locating and securing stop.
7~3
--5--
Figure 5 is an elevational view showing a spring clip
of the compensator as see~ ~rom the left end of Figure 1.
Figure 6 is a side elevation of another compensator
embodying the present invention, showing the compensator in
position for use by a right handed rifleman and also showing a
modified means for securing the compensator in a rotatably
adjusted position on a flash hider.
Figure 7 is an end elevation from the left or front
end of Figure 6.
Figure 8 is an elevational view of the compensator of
Figure 6, looking in the direction of arrow 8 in Figure 7.
Figure 9 is a side elevation of an alternative compen-
sator.
Figure 10 is a transverse sectional view looking right-
lS ward, showing thecompensator of Figure 9 mounted on a flash
hider.
Figure 11 is a side elevation of the compensator of Fig-
u~e 9 adjusted for a left~handed rifleman.
Figure 12 is a side elevation of another modification of
a compensator embodying the invention, shown in position for
a bipod mounted weapon.
Figure 13 is a transverse sectional view looking left-
ward, showing the compensator of Figure 12 mounted on a
flash hider and adjusted for a right handed rifleman.
Figure 14 shows the compensatorof Figure 12, looking in
the direction of arrow 14 of Figure 13.
Figures 15 through 29 are schematic cross-sectional
views illustrating various modification of compensators
embodying the present invention and adapted respectively for
use with specific types of guns and flash hiders. The views
may be considered as seen from the muzzle end, wherein:
Figures 15 and 17 show a compensator adjusted for left
and right handed riflemen respectively and suitable for use
with a flash hider having four sets of flash hider ports
located with respect to the hour hand of a clock at 2:00,
4:00, 8:00 and 10:00 o'clock.
Figur~ 16 shows the compensator of Figures lS and 17
adjusted for bipod mounting.
I 1 673~3
Figures 18 and 20 are views similar to Figures lS and
17 respectively, but showing ~ compensator suitable for use
with five sets of flash hider ports arranged at 12 o'clock
and at 72 intervals.
Figure 19 shows a co~pensator adjusted for bipod mount-
ing and useful with a flash hider having ports arranged as
in Figures 18 and 20.
Figures 21 and 23 are views similar to Figures lS and
17 respectively, but showing a compensator suitable for use
with six sets of flash hider ports arranged at 12 o'clock
and at 60 intervals.
Figure 22 shows the compensator of Figures 21 and 23 ad-
justed for bipod mounting.,
Figu~es 24 through 26 are views similar to Figures 21
through 23, showing a modified compensator.
Figures 27 through 29 illustrate three additional
modifications of compensators embodying the present
invention.
Referring to Figures 1 through 5, a compensator 29 for
a gun is shown comprising an elongate tubular element or
body portion 30 dimensioned to fit snugly around the cylind-
drical exterior of a flash hider 31 at the muzzle end of a
gun barrel 32 and to be rotatable coaxially thereon to
ac,commodate various firing conditions as explained below.
The element 30 has an outlet end 33 with an opening 34
aligned with the rifled bore portion 35 of the barrel 32
through which a projectile can pass~
The flash hider 31 may be a conventional type having
four sets of flash hider ports 36 spaced circumferentially
90 apart and located with eeference to the hour hand of a
I 1 6r73~3
! f~
clock at 1:30, 4:30, 7:30 and 10:30, as shown in Figure 2. Each
set of ports may comprise ,three separate holes spaced
axially of the barrel as shown in Figure 4, or may comprise
one or more axially extending slots, or other suitable
arrangements. In the present instance, the ports 36 extend
radially through the cylindrical wall of the flash hider 31
from its central bore 37 ~hich is enlarged with respect to
the bore of the rifled portion 35. The bore 37 also ex-
tends coaxially beyond the muzzle end of bore portion 35 to
provide an expansion chamber into which the gases propelling
the b~llet or ~rojectile may expand. The expanded g~ses are
then discharged transversely of the axis of the barrel 32.
The function of the flash hider in expanding, cooling and
breaking-up a portion of the axial gas flow into a number of
transverse streams so as to reduce the overall visibility of
the flash is well known to the art and is accordingly not
discussed further.
A central axially elongated vent 38 extends radially
through the cylindrical wall of the element or body portion
30, Two essentially diametrically o~posed side vents 39 of
similar and parallel shape to the vent 38 are formed in the
element 30 at circumferentially spaced locations at o~posite
sides of the vent 38 which is usually but not necessarily
spaced 90 therebetween. Deflectors 40 are formed adjacent the
vents 3g and serve to deflect combustion gases that are
discharged transversely from the ports 36 generally in the
direction o~ arrows 51, Thus the combustion gases pas-
sing through the vents 38 and 39 are directed primarily up-
wardly and at approximately 45 to one side of a vertical
axial mid-plane of the barrel 32 when the gun is in a firing
position. It is also to be noted that ~it'~o~t the de~lec-
tors 40, the reaction forces of gases discharged f~om the
aligned flash hider ports 36 would neutralize each other and
have no lift compensating effect.
For securing the element 30 onto the flash hider 31, a
lever 41 is pivotally mounted on pin 42 between mounting
ribs 43 on the element 30. A stop 44 on the lever 41 passes
into the interior of the element 30 through a radial hole 45
673~3
--8--
in the peripheral wall of the element. The stop 44 can en-
gage in a s~itable ~lash hider port 36 in the 1ash hider 31
of the barrel 32. A spring clip 46 mounted on the lever 41
can serve to hold it in the position shown. A retaining
S catch 47 of the lever 41 engages the rear end of flash hider
31 to assist in locating and in preventing forward movement
of the stabilizer 29. An inner wall 48 of the element 30
prevents its backward movement by engagi~g the muzzle end of
the flash hider 31.
As shown in Figures 1 through 5, spring clip 46 is pivo-
tally mounted on a pin 49 at the free end of the lever 41
and is partly circular so that it may partly encircle the
flash hider 31 or other portion of the barrel 32 and remain
in position by virtue of its own resilience. As long as the
clip 46 remains in the position shown, the lever 41 keeps
the stop 44 in the appropriate port 36 and the element 30
is held in place. The stop 44 can be cetracted from the
poct 36 by releasing the spring clip 46 by merely applying
p~essure to the latters outwardly bent region so and spring-
ing the clip 46 off the barrel 32, thus enabling thecompensator 29 to be rotatably adjusted to another position
or to be removed rapidly from the gun. Re~oval of the ele-
ment 30 is necessary, for example, when the rifle is to be
used to launch a rifle grenade accurately. In this regard,
the lever 41 in the open or unlatched position facilitates
mounting of the compensator 29 on a hot gun barrel and is
sufficiently long so that it cools rapidly to facilitate
removal of a hot compensator 29. The vents 38 and 39
referred to can be either elongated slots or holes or a
combination of slots and holes to suit any particular ar-
rangement of flash hider ports of any gun barrel.
The compensator of the type shown in Figures 1 through
S may also be designed for use with the flash hider usually
provided for the 'NATO FN FAL' infantry rifle. ~,hen holding
such a rifle in its firing position, the marksman can see
certain flash hider gas exhaust ports. There are twelve
such ports in all, and these can be numbered in four series
of three ports each. Proceeding in a clockwise direction
~ ~ 673()3
g
as seen by the marksman, series 'A' would be in the 1:30
o'clock position; series 'B' would be in the 4:30 o'clock
position; series 'C' would be in the 7:30 o'clock
position and series 'D' would be in the 10:30 o'clock
position. For a right-handed marksman the compensator 30 is
mounted on the flash hider so that the ports of series 'A'
are aligned with a central vent 38, enabling combustion gas-
es expelled through the series 'A' ports to escape without
deflection. The vents 39 may be merged with vent 38, as
illu~:trated in Figures lS and 17 and the deflectors 40 will
be located respectively adjacent to the three ports of
series 'B' and the three ports of series 'D'. The gases
from the latter six ports strike the deflectors 40 which
redirect the gases from thei~ natural transverse path so
that they are exhausted in the general direction of the
arrows 51, Figures 2 or 17, to effect a reaction force
against the barrel 32 opposing the muzzle lift. The ports
of series 'C' are closed by a cylindrical port restricting
portion as described below.
Because the stop 44 engages in a flash hider port 36,
it is possible for right or left handed people to use the
same compensator. The letter 'R' on the compensator 30 of
Figure 3 is uppermost on the gun barrel when right-handed
people are to use the compensator. The letter 'L' will be
uppermost for left-handed people. In each case, a port 36
in a different series of flash hider ports is engaged by the
stop 44. Por a left handed marksman the compensator 29 is
mounted on the flash hider 31 so that the ports of series
'D' are aligned with a central vent 38, enabling combustion
gases expelled through these ports to escape without deflec-
tion. The vents 39 will be aligned with and the defle~to~s
40 will be located adjacent to the three ports oE series 'A'
and with the three ports of series 'C' respectively to
effect a reaction force against the barrel 32 opposing the
muzzle lift.
Without the stabilizer, the NATO FN FAL infantry rifle
used by a right handed marksman, when fired on automatic,
has a definite tendancy to rise upward and to the right at
I 1 673~3 --
--10--
an angle of approximately 45. Even if the marksman holds
the weapon firmly, the result is highly inaccurate rifle
fire with most of the bullets striking above and to the
right of the target. This means that automatic fire is
5 - wasteful and ineffective due to the high rate at which bul-
lets are expended inaccurately. For 'double tap' shooting,
i.e., when the rifle is fired with single rounds in bursts
of two shots fired in rapid succession by double-tapping the
trigger, the marksman has.to re-aim for each 'double tap'
becauseof the tendancy of the weapon to rise. Also, when
firing single rounds without the compensator, the weapon
tends to rise upward and to the right, althou~h the muzzle
lift is less noticeable than with fully automatic firing.
There is a need to re-aim for each shot, otherwise inac-
curate ire will result. Similar problems arise for lefthanded marksmen but the tendency is for the rifle to rise to
the left. Similar problems are encountered with most auto-
matic weapons.
Once the compensator is properly attached to the rifle,
the tendency of the rifle muzzle to rise is largely removed.
This means that the rifle is more accurate and can be fired
more efficiently. When the compensator is held firmly in
place on the rifle, there is a tendency for the compensator
to pull the weapon forward away from the marksman and there-
by to reduce shoulder recoil. Due to a reduction of therecoil, fire with the compensator can be more accurate than
without it.
The compensator can be quickly and easily removed from
or replaced on a rifle barrel or flash hider without the u~e
any tools. Thus the cifle can still be used with rifle gren-
nades, blank firing attachments, bayonets, and othec acces-
sories. The weapon requires absolutely no alteration in
order to enable use of the compensator. The deflectors 40
can also be positioned and dimensioned to redirect gases so
as to neutralize any bias, lift or movement experienced with
guns which are mounted, whether permanently or temporarily
to bipods, tripods, wheels or any fixed or temporary pedes-
tals. The compensatocs illustrated and described herein
` 1 3 6~303
can be manufactured from a variety of steels or ferro~s or
non-ferrous materials at relat~ively low cost and can be of
fairly light weight construction that will not significantly
affect the overall weight of the weapon to which it is atta-
ched.
Although the compensator has been described above with
reference to use on an FN FAL in~antry rifle, the compen-
sator can be used on other types of guns. The specific
design of the compensator can be readily tailored to accom-
modate other types of guns, barrel diameters and flash hiderdesigns without departing from the basic compensating fea-
tures described herein.
Referring to Figure~ 6 through 8, a modified compensa-
tor 29 is shown wherein the outlet end 33 has a part-spheri-
cal deflector 52 for deflecting combustion gases from thegun barrel generally in the direction of arrow 51a in
Figures 6 and 7.
Although the opening 34 in Figure 7 appears to be sub-
stantially circular when vie~ed axially of the element 30,
it is in fact slightly elliptical because it is inclined to
the longitudinal axis of the element 30. The central vent
38 and the essentially diàmetrically opposed vents 39 are
formed substantially as described above. Deflectors 40 are
formed adjacent to the vents 39 and serve to deflect com-
bustion gases therefrom generally in the direction of arrows51 in Figure 7. Thus, the combustion gases passing through
the vents are directed primarily to one side of the element
30 as described above.
By virtue of the muzzle deflector 52, the circumfer-
ential extent of the deflectors 40 may be minimized. How-
ever, the deflectors 52 for each of the com2ensators des-
cribed can be eliminated by suitably dimensioning the
deflectors 40 as illustrated in Figures 15 through 23 or by
providing gas transfer channels in the element 30 to guide
3S combustion gases circumferentially around a portion of the
flash hider from its ports located below the horizontal
axial plane of the barrel, as illustrated in Figures 24
through 29 for example.
1 6 7 3 0 3
-12-
The cylindrical body of the element 30 in Fig~lres 6
through 8 is provided with rearwardly opening and axially
extending slots 53. A clamping or securing device may be
located around the slotted end portion of the element 30 and
S tightened to clamp the compensator onto the flash hider 31.
The compensator 29 shown in Figures 9 through 11 also
has means for securing it in a rotatably adjusted position
on a flash hider 31 and has an outlet end 33 substantially
identical to that of Figures 6 through 8. However, the com-
pensator of Figures 9 through 11 has three substantially
rectangular vents 54 which are separated from one another by
elongated reinforcing fins 55 extending axially along the
periphery of the element 30. The vent 54 between the fins
55 acts in much the same way as the vent 38 of Figure 8, and
lS thus directs combustion gases generally in the dlrection of
arrow 56, Figure 10. The other two vents 54 may be spaced
essentially 90 in opposite directions from the central vent
54 and each is formed between a fin 55 and a deflector 40.
The latter is similar to the corresponding deflector 40 of
Figures 1 to 3, and the deflectors 40 and fins S5 of Figures
9 through 11 serve to deflect combustion gases substantially
in the direction of arrows 57 in Figure 10. Thus the vents
and deflectors again serve to direct combustion gases
primarily to one side of the compensator 29.
Further in regard to the deflectors 40 shown in any of the
drawings herein, the deflectors extend generally axially of
the gun barrel 32 for approximately the effective axial
extent of the flash hider ports 36 and are preferably closed
or connected to the adjacent portion o~ the cylindrical
element 30 at their axially opposite edges by end bracket
portions 4a. The forward bracket 40a or end closure adjacent
the muzzle end serves to ~educe recoil when impinged by
escaping gases. 30th brackets 40a serve to reinforce the
deflector and to prevent its catching on bushes, etc.
The means for securing the compensator 29 of Figures 9
through 11 onto a flash hider 31 comprises a lever 58 pivot-
tally mounted at 59 on a mounting 60 of the element 30 and
pivotally biased by spring 61, Figure 11, so that a stop 62
1 1 673~3
.~
-13-
62 on the lever 58 passes int~ the interior of the element
30 through a radial hole 63 therein. The stop 62 can engage
in a suitable notch in the barrel or in a flash hider port
36 as above described. The spcing 61 can serve to hold the
stop 62 in the notch. The stop 62 can be retracted against
the biasing action of the spring 61 by applying pressure to
the lever 58 in the region of the spring 61, thus enabling
the compensator 29 to be removed from the flash hider 31 or
to be adjustably rotated from one preselected position to
another.
The compensator 29 of Figure 12 through 14 also has a
tubular cylindrical body portion 30 dimensioned to fit
snugly onto a flash hider 31 and has an outlet end 33 with
an opening 34 through which a projectile can pass. The
element 30 in these Figures has vents 38 and 39 and
deflectors 40 similar to those described in regard to
Figures 2 and 3. A curved portion 52 of the outlet end 33
provides a further deflector for axial combustion gases, as
described above. The compensator of Figures 12 through 14
has an attachment device 64, which is not shown in detail as
it is similar to that for conventionally securing a bayonet
onto a flash hider or a rifle barrel. However, the device
may include a catch or stop similar to the stops 44 and 62
for engaging ~ notch in the flash hider or barrel.
It is believed to be apparent that by oroviding a com-
pensator adapted to be rotatably adjusted on a flash hider
and having suitable circumferentially spaced deflectors,
vents, and port closing or restricting po~tions selectively
positionable with respect to the flash hider oorts in
accordance with the adjustment, com~ensation for practically
any angle of muzzle climb can be obtained from any flash
hider in common use. For optimum efficiency, it will, of
course, be necessary to design the gas control means of the
compensator to meet the specific requirements of each flash
hider, gun, and mode of firing. Figures 15 through 29
illustrate the versatility of the present inventions by
showing several adaptions to various conventional flash
, 1 1 6~303 L
-14-
hider port arrangements. Each view is a schematic section
of a compensator mounted on a flash hider, as viewed from
the muzzle end, and of course, the structural concepts
illustrated in any of the views herein may be used with
S the compensators illustrated in any other view herein.
In Figures 15 through 17, four flash hider ports 36 or
sets thereof are located at the two, four, eight and ten o'
clock positions when the gun is in its normal ~iring posi-
tion with its sight at twelve o'clock. The compensator 29
is similar to those described above, except that the central
vent 38 is widened circumferen~ially to expose the two o'
clock port 36, as seen in Figure 15, for le~t hand shooting,
or to expose the ten o'clock port 36 when the compensator 29
is rotated to the Figure 17 position for right hand shoot-
ing, or to expose both the two and ten o'clock ports 36 when
the compensator 29 is rotated to the Figure 16 position to
oppose vertical lift when the gun is mounted on a bipod.
As illustrated in Figures 15 through 17, the vents 38
and 39 described above may be merged into a single large
ce~tral vent opposite the cylindrical vent restricting
portion 70 which sunstantially closes the eight o'clock port
in Figure 15 and the four o'clock port in Figure 170
Inasmuch as the compensator positionC in Figures lS and
17 are not necessarily 120 apart, the slits 53 and a
clamping band may be used to secure the compensator 29 at
its adjusted position, or more than one circumferentially
spaced locating stop 44 may be used for selectively align-
ing one thereof with a port 36 that is closed by restrict-
or 70 at each position of adjustment. Where reinforcement
of the vented region of the compensator is required, cir-
cumferentially spaced cylindrical portions of the element 30
may be provided, as in Figure 2, overlying pottions of the
flash hider 31 opposite restrictor 70 and such overlying
cylindrical portions may be reinforced, as for example, by
ribs 55 as in Figures 9 and 10.
Figures 18 and 20 show the left and right hand firing
positions for a compensator 29 rotatably adjusted on a flash
hider 31 having five ports 36, including one at twelve o'
I 1 ~ 7~(~3
-15-
clock and at 72 interval therefrom, wherein the cylind-
rical port restricting portion~ 70 of the element 30 extends
around the majoc circumference of the flash hider 31 to
close all of its ports 36 except the twelve o'clock port 36
and the clockwise adjacent port 36 when rotated to the left
hand firing position of Figure 18, and except the twelve
o'clock port and the counterclockwise adjacent port when
rotated to the right hand firing position of Figure 20. In
Figures lS through 20, the two deflectors 40 which extend
axially of the circumferentially spaced edges of the port
restricting portion 70 as illustrated in Figures 3, 8 and 9,
for example, also diverge from the cylindrical contours of
the portion 70 adjacent to said edges and overlap the two
po~ts 36 respectively that are not closed by the portion
70, thereby to redirect the gases impinging against the
deflectors 40 essentially in the direction of the associated
arrows to effect a desired resultant reaction force general-
ly in the direction of the arrow 71 opposing muzzle lift.
Where the cylindrical portion 72 between the vents 39
is not required for reinforcement, it may be eliminated asin Figures lS and 17. The two vents 39 will then be merged
into a single larger vent.
Figure l9 illustrates a compensator 29 on a five port
fla~h hider 31 of the type illustrated in Figures 18 and
19 but in position to compensate for vertical lift of a hand
gun or bipod mounted gun. A central vent 38 aligns with the
twelve o'clock flash hider port 36 and the lateral vents 39
align with the flash hider ports 36 spaced 72 in opposite
directions therefrom. The compensator 29 of Figure l9 may
also be rotated in either direction from the position shown
to align vent 38 selectively with either of the ports 3O
adjacent the twelve o'clock port 36 and compensate for left
or right hand muzzle climb.
Figures 21 through 23 show a modified compensator 29
suitable for use with the five port flash hider of Figures
18 through 20 or with a six port flash hider having a twelve
o'clock port and five additional ports spaced therefrom at
60 intervals. Each deflector 40 deflects gas discharged
'~ 1167303 -
-16-
for more than one flash hider port and only one port is
closed by the restrictor 70. Accordingly improved flash
hiding is achieved, rendering the compensator of Figures 21
and 22 more suitable for use with higher powered guns,
as compared to the compensator of Figures 18 through 20. As
in Figure 19, the cylindrical portion of element 30 opposite
the cylindrical port restricting portion 70 is partitioned
into two circumferentially spaced parts 72a and 72b to
provide the central vent 38 therebetween. The lateral vents
39 are enlarged circumferentially to extend from the
circumferentially spaced edges of the restrictor 70 to the
adjacent portions 72a and 72b respectively and each com-
municates with two flash hider ports 36 to discharge
gases there~rom, which gases are then redirected by the
deflectors 40 in the general direction of the associated
unnumbered arrows to effect a resultant reaction fo~ce in
the direction of the arrow 71 to compensate for muzzle
climb.
The compensator 29 in Figure 22 is adjusted for bipod
support to compensate for vertical lift. The compensators
29 in Figures 21 and 23 are rotated 60 in opposite
~icections from the Figure 22 position to compensate for
left and right handed muzzle climb. Indexing the adjusted
. position of the compensator 29 in Figures 21 through 23
through 60 intervals enables the stops 44 and 62 to be
readily used to secure the compensator in its adjusted
angular position, but as described above in regard to Fig-
ures 15 through 17, the 60 indexing is not essential.
Any angular adjustment may be made as desired and the
resultant reaction force may be directed precisely in any
direction by suitable angular adjustment of the compensator
29 with respect to the flash hider and/or by predetermining
the angularity of the deflectors 40 and the locations and
dimensions of the vents 38 and 39.
Figures 24 through 26 illustrate a modification which
1 ~67303
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further enhances the flash hiding effect o~ the flash hider
31 and enables use of most of the flash hider ports. The
cylindrical restricting portion 70 is spaced radially from
the flash hider 31 to provide a gas passage 73 communicat-
ing with the flash hider pocts 36 within the arc of theportion 70. Gases flowing from such ports are redirected
circumferentially and discharged via the vents 39 in the
directions determined by.the deflectors 40. Such gases in
cooperation with gases discharged radially from the unres-
tricted port 36 at each position effect a resultant reactionforce in th~ direction of the arrow 71. The reaction
direction will be vertical in Figure 25 and approximately
45 from the vertical at the left and right hand firing
positions of Figures 24 and 26 respectively, whereat the
compensator 29 is rotated approximately 45 in opposite
directions from the Figure 25 bipod position.
Figure 27 illustrates the concept of multiple deflect-
ors 40 at opposite sides of the plane of symmetry of the
compensator 29. As in the other views, the deflectors com-
prise paired mirror images that, with or without the pass-
ages 73, or 73a of Figure 28, enable use of flash hider
ports 36 that would otherwise discharge below the horizon-
tal, thereby to increase the effectiveness of the com-
pensator 29 at various rotational positions of adjustment
without seriously impairing the effectiveness of the flash
hider 31.
~ igure 28 shows a compensator 29 detachably mounted
rotatably on a flash hider 31 having a port 36 at twelve
o'clock and every 45 interval there~rom except at six
o'clock. The restrictor 70 is centered diametrically oppo-
site the twelve o'clock port 36 and partially restricts the
ports 36 at 4:30 and 7:30 o'clock when the compensator is
adjusted to compensate for vertical lift. The figure 28
construction is particularly suitable for 45 rotation in
either direction from~the position shown to oppose left or
right handed muzzle climb, as described above, whereat the
restrictor 70 will close the 7:30 o'clock port 36 or the
4:30 o'clock port 36, respectively. The deflectors 40
I 1 673() 3
-la-
extend circumferentially around the flash hider 31 in
spaced relationship to deflect gases discharged trans-
versely from more than one port 36 and to provide a pair of
passages 73a comparable to the passage 73, except that each
passage 73a opens in only one direction. The restrictor 70
is in sliding and essentially sealing engagement with the
cylindrical surface of the flash hider 31 so as to close any
port 36 with which it is aligned in the event that over
compensation is a problem.
In Figure 28, gases are discharged from all of the
flash hider ports. Although the gas discharge from several
ports 36 is concentrated by the compensator, the expansion
and turbulence of the gases within the passages 73a rapidly
dissipates the heat energy of the gases and, aided by the
heat lost by conduction through and radiation from the
deflectors 40, preserves much of the effectiveness of the
flash hider 31 without the compensator 29 mounted thereon.
Figure 29 shows a modification similar to Figure 28,
except that the restrictor 70 is spaced throughout its cir-
cumferential extent from the flash hider 31 and the latter
has six ports 36 including one at the six o'clock position
and at 60 intervals thereafter.
In addition to Ellis et al, patent number 3,971,285,
the following patents are the most pertinent references re-
lating to the present invention know~ to applicants:
British Patent No. 606l478 - Galliot
French Patent No. 1,262,942 - I~oulin
U.S. Patent No. 2,065,273 - Galliot
U.S. Patent No. 3,179,011 - Rahm
None of the above and no reference ~nown to applicants
teach the concept of a compensator removably mountable on a
flash hider for rotatable adjustment to various selected
positions and having deflector~ cooperable with selected
flash hider pocts at each position for utilizing the gases
discharged transversely therefrom and for redirecting those
gases to compensate for a particular angle of muzzle lift.
Ellis et al shows a rotatable compensator that also has some
flash hiding function, but in addition to the distinction
1 ~ 67 3 ~) 3
-18a-
and deficiency noted above, ~hey are limited to the use of
flash hider ports that discharge upwardly.
The devices in the remaining references are intended
for hand guns or machine guns on fixed mountings. They are
not rotatable to compensate for other than vertical lift,
and even if they were, they would not teach applicants'
additional concept of providing a removable compensator that
enables use of the flsh hider for grenade launching, for
example, and that is also rotatably adjustably on the flash
hider to predetermine the angle of lift compensation.
