Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a plastic frangible training projectile
and, more particularly, the invention is concerned with pro~iding a training
projectile encapsulated in a thermoplastic material so that it ~reaks up on
impact with the target or ground ~o avoid the hazards associated with long
ricochets
~leretofore, it has been the common practice to provide practice
cartridges for small arms and automatic weapons which disintegrate immediately
after leaving the muzzle of the gunO Generally, this is accomplished by pro-
viding a plastic casing which is filled with an inert material and sealed
with a cap of the same plastic. The attempt is made to duplicate as nearly
as possible, the shape and weight of the comparable live projectile. When
this requirement is met, i~ is possible to use the round in an automatic
weapon without detrimental effect on the breech and loading mechanism. The
operation of the entire gun mechanism depends upon the buildup of a pre-
determined gas pressure in the powder chamber which is controlled partly by
the weight and shape of the bullet. Also, the bullet must remain intact until
it leaves the muzzle of the gun to preven~ damage to ~he gun caused by escape
of ~he filling ma~erial into the barrel with the resultant high barrel wear,
Many designs have been prepared in an attempt ~o overcome these
problems. Included in these designs are projectiles having axially extending
grooves which cause the casing to tear axially and releas the filler material
~herefrom. This disintegra~ion of the presently known-target projectiles
occurs immediately after leaving the barrel so as not to do any damage beyond
a predetermined distance from the barrel muzzle. l~is arrangement, of course,
results in a sys~em which does not simulate actual firing conditions and is
of limited use in training personnel in the use of equipment or practice and
is of no use whatsoever for target practice.
Thus, it would be especially advantageous to provide a plastic
frangible training projectile that disintegrates on impact with a target or
the ground. This type of training projectile would eliminate the hazards of
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long ricoche~s especially to the civilian populace in the area of ranges on
air bases used for air-to-ground gunnery practice. Also, it would be desir-
able to lower the cost-per-unit of training projectiles currently used for
target practice while substantially lessening gun barrel deterioration caused
by the interaction between the copper rotating band and the barrel. In general,
a sense of reality should be imparted to personnel being trained so that a
high degree of interest and enthusiasm can be produced resulting in a truly
worthwhile training exercise.
The present invention provides a plastic frangible training projec-
tile for firing through a weapon having a rifled bore comprising a plasticjacket having an open central portion and an ogival shaped head portion, means
within the open central portion of said projectile for effectively controlling
the center of gravity and weight of said projectile, such that the firing of
the projectile simulates the flight properties of a live round of ammunition
of the same caliber.
One embodiment has a rearwardly extending open central area in which
a series of washers or platelets are positioned. A pusher plate is placed at
the rear of the interior of the projectile which may then be enclosed with a
plastic base cap. A rotating band may be provided which is integral with the
jacket and made of the same material. The projectile remains intact in flight
and breaks up on impact so as to eliminate long ricochet with the accompanying
dangers to personnel and equipment in the target area.
Such an improved frangible training projectile that is useful in
air-to-ground target practice and yet does no~ require extensive vacant space
in the target area in order ~o prevent damage from long ricochet. The amount
of inertia, weight and the center of gravity of the projectile can be easily
altered to meet the requirements of a particular ballistic system. The
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projectile which is relatively easy and economical to manufacture using
non-strategic materials by presently known production techniques. Gun
barrel deterioration due to interaction between the copper rotating band
and the barrel are substantially reduced by providing the projectile
with an integral plastic rotating band.
These and other objects, features and advantages will become
more apparent after considering the following description taken in con-
junction with the accompanying drawing and appended claims.
Figure l is a view of the plastic frangible training projectile
according to the invention in completely assembled condition;
Figure 2 is a view taken along the line 2-2 of Figure l showing
the plastic jacket in longitudinal cross section including the internal
elements with the plastic base cap ready for insertion; and
Figure 3 is a view of another embodiment of the invention showing
the use of platelets in the open central portion of the projectile.
Referring now to the drawings, there is shown a plastic frangible
training projectile 13 preferably made of thermoplastic material with rotat-
ing band 15 of the same material encircling the body. The thermoplastic
material of which the projectile 13 is fabricated may be polyethylene, glass
filled nylon, hard polyvinyl chloride or the like. The use of these materials
having different specific weights makes it possible to easily alter the
moment of inertia, weight, and center of gravity of the projectile by select-
ing the volume and dimensions of the plastic components and correspondingly
matching the proportions thereof to the overall volume and dimension of the
projectile 13 to match it to specific ballistic requirements.
Referring to Figure 2, a jacket 19 includes an ogival head portion
21 and the elongated cen~ral rod-like portion 23 extending rearwardly there-
from. The ogival head 21 and central rod-like portion 23 are preferably fab-
ricated of plastic in single one-piece construction along with the rotating
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band 15. A series of washers 25 made of steel, for example, include centralopenings which are dimensioned to slide over the central rod-like portion
23 of the jacket 19. The number and size of the washers 25 can be varied to
thereby determine the total weight and control the positions of the center
of gravity of the projectile 13 so as to more accurately simulate the con-
ditions of actual firing of live ammunition. After the washers 25 are attached,
a steel pusher plate 27 is inserted into the opening of the jacket 19 so that
the projection 29 abuts the rearward end of the member 23. An end cap 31 of
plastic is ultrasonically welded into the open base of the jacket 19 to com-
plete the assembly of the training projectile 13. By such welding one integral
piece is formed and ~he parts inside thereof are completely sealed.
In smaller caliber weapons, for example, the embodimen~ shown in
Figure 3 wDuld be more appropriate. In this type frangible projectile 13,
a jacket 23 includes an ogival head 35 which effectively encloses the forward
end of a central opening 36 in which a series of platelets 37 are positioned.
These platelets 37 serve the same purpose and f~ction as the washers 25 in
the embodiment of Figure 2. It should be noted that, although the projectile
13 has been depicted as having an integral head and body portion, it could be
fabricated with a separable ogival head 35 and an integral closed end cap.
In this latter structural arrangement, the platelets 37 would be loaded from
the front of the projectile and the ogival head 35 would be ultrasonically
welded in position after assembly. Also, the platele~s 37 could take ~y
appropriate shape so long as ~chey remain symmetrical and provide the necess-
ary weight and gravita~ional characteristics to the projectile. For example,
the platelets 37 could have notched peripheral edge surfaces so that the
weight could be more effectively distribu~ed.
When the projectile is fired during training at a target on a
gunnery range, for example, the jacket 19 ruptures on impact causing the
projectile 13 to disintegrate immediately thereafter. Since th0 projectile
13 ruptures immediately on contact with the target, the hazards of long rico-
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chets are entirely eliminated and the size and location of the gunnery r~lge
becomes far less critical. lhe plas~ic jacket 19 ruptures more easily than
a comparable metal jacket thereby causing the projectile to disintegrate and,
in addition, has the advantage of being lower in cost and causing less wear
in the weapon barrel.
The improved plastic frangible training projectile according to the
invention is providcd with thermoplastic jackets 19 and 33 which also serve
as a windshield to reduce aerodynamic drag of the projectile and thus minimise
energy loss during flight to the target. A rotating band 15 of plastic encir_
cles the jacket 19 and is integral therewith for engaging the rifling in the
gun bore thereby signific~ntly reducing the friction of the projectile body
as it is forced through the gun bore while greatly improving the efficiency
of the weapon operation.
It is thus seen that a projectile has been described which is simple
in operation and easily manufactured as well as far safer for use on a gunnery
range which is near populated areas. This feature is accomplished without
producing undue wear or causing damage ~o the gun bore as the projectile passes
~herethrough. There is experimental data which indicates that barrel life in
a 20 mm canon which utilises training projectiles of the type hereinbefore
described can be increased by a factor of three. Also, ~he plastic project-
ile provides a highly effective training means while at the same time reducing
the use of critical material (copper)~
Although the invention has been illustrated in the accompanying
dra~ings and described in the foregoing specification in terms of a preferred
embodiment thereof, the invention is not limited ~o this embodiment or to
the preferred configuration mentioned. It will be apparent to those skilled
in the art that my invention could have extensive use in other operations
where it is desirable to provide a plastic frangible training projectile that
is less expensive to manufacture as well as providing safer air-to-ground gun
ranges in terms of fewer ricochets because of excellent projectile break-~) on
impact even at a thirty degree angle to the horizontal.
