US3902683A

US3902683A - Plastic frangible training projectile

Info

Publication number: US3902683A
Application number: US413728A
Authority: US
Inventors: Stephen J Bilsbury
Original assignee: United States Department of the Air Force
Current assignee: United States Department of the Air Force
Priority date: 1973-11-07
Filing date: 1973-11-07
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02
Also published as: FI56073C; DK577774A; CS185662B2; DK140415B; CH598561A5; CA1048342A; GB1463347A; AU498571B2; DK140415C; SE7413628L; LU71246A1; IL45504A; IT1023165B; FR2250092A1; FI56073B; DE2444488A1; DE2444488C2; SE410519B; IL45504A0; JPS5079200A

Abstract

A plastic frangible projectile especially useful in training exercises to break up instead of ricocheting on impact. An injection molded jacket with an integral rotating band is made from a thermoplastic material and includes an open central portion extending rearwardly from an ogival head portion. A plurality of washers or platelets fit in the central portion of the plastic jacket with a pusher plate behind and the projectile is enclosed on the bottom by a plastic base cap.

Description

States atet 1191 Bilsbury Sept. 2, 1975 [54] PLASTIC FRANGIBLE TRAINING 3,429,263 2/1969 Snyder et 211. 102/92.7 PROJECTILE 3,439,619 4/1969 BOCk 61 al 102/41 3,785,293 1/1974 Barr .1 102/41 [75] Inventor: Stephen J. Bilsbury, Shalimar, Fla.

[73] Assignee: The United States of America as Primary Examiner-Robert F. Stahl represented by the Secretary of the Attorney, Agent, or FirmJoseph E. Rusz'; Arsen Air Force, Washington, DC. ashjian [22] Filed: Nov. 7, 1973 [57] ABSTRACT [21] Appl. No: 413,728

A plastic frangible projectile especially useful in training exercises to break up instead of'ricocheting on im- [52] U.S. C1 244/3.1; l02/92.7 pact An injection molded jacket i an integral [51] 1131;. C1. F421) 5/22; F42b 1 1/36 tating band i made from a thermoplastic material and [58] F1eld of Search lO2/4l 92.7, 38, 92.3, includes an open central portion extending rearwardly 43 P; 244/3-1 from an ogival head portion. A plurality of washers or platelets fit in the central portion of the plastic jacket [56] References Cited with a pusher plate behind and the projectile is en- UNITED STATES PATENTS closed on the bottom by a plastic base cap.

2,593,637 4/1952 Weldin 102/41 3,181,465 5/l965 Anthony 102/41 3 Clams 3 Drawmg figures PLASTIC FRANGIBLE TRAINING PROJECTILE BACKGROUND OF THE INVENTION This invention relates to a plastic frangible training projectile and, more particularly, the invention is concerned with providing a training projectile encapsulated in a thermoplastic material so that it breaks up on impact with the target or ground to avoid the hazards associated with long ricochets I-Ieretofore, 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 gun. Generally, this is accomplished by providing 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, it 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 predetermined 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 prevent damage to the gun caused by escape of the filling material into the barrel with the resultant high barrel wear.

Many designs have been prepared "in an attempt to overcome these problems. Included in these designs are projectiles having axially extending grooves which cause the casing to tear axially and release the filler material therefrom. This disintegration 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. This arrangement, of course, results in a system which does not simulate actual firing conditions and is of limited use in training personnel in the use of equipment for 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 long ricochets especially to the civilian populace in the area of ranges on air bases used for air-to-ground gunnery practice. Also, it would be desirable to lower the costper-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.

SUMMARY OF THE INVENTION The present invention is concerned with providing a plastic frangible training projectile having a plastic jacket including a solid head portion with a rearwardly extending 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.

Accordingly, it is an object of the present invention to provide an improved frangible training projectile 5 that is useful in air-to-ground target practice and yet does not require extensive vacant space in the target area in order to prevent damage from long ricochet.

Another object of the invention is to provide a frangible training projectile having a plastic case with an integral rotating band of the same material. The projectile is frangible only on target impact and avoids the hazards associated with long ricochets.

Still another object of the invention is to provide a plastic frangible training projectile wherein 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.

A further object of the invention is to provide a plastic training projectile which is relatively easy and economical to manufacture using non-strategic materials by presently known production techniques.

A still further object of the invention is to provide an improved plastic training projectile wherein the 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 conjunction with the accompanying drawing and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of the plastic frangible training projectile according to the invention in completely assembled condition;

FIG. 2 is a view taken along the line 2-2 of FIG. 1 showing the plastic jacket in longitudinal cross section including the internal elements with the plastic base cap readyfor insertion; and

FIG. 3 is a view of another embodiment of the invention showing the use of platelets in the open central portion of the projectile.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings, there is shown a plastic frangible training projectile 13 preferably made of thermoplastic material with rotating 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 selecting 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 FIG. 2, a jacket 19 includes an ogival head portion 21 and the elongated central rod-like portion 23 extending rearwardly therefrom. The ogival head 21 and central rod-like portion 23 are preferably fabricated of plastic in single one-piece construction along with the rotating band 15. A series of washers 25 made of steel, for example, include central openings which are dimensioned to slide over the central rodlike 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 conditions 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 complete the assembly of the training projectile 13. By such welding one integral piece is formed and the parts inside thereof are completely sealed.

ln smaller caliber weapons, for example, the embodiment shown in FIG. 3 would be more appropriate. In this type frangible projectile l3, ajacket 33 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 function as the washers 25 in the embodiment of FIG. 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 platelets 37 could take any appropriate shape so long as they remain symmetrical and provide the necessary weight and gravitational characteristics to the projectile. For example, the platelets 37 could have notched peripheral edge surfaces so that the weight could be more effectively distributed.

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 the projectile l3 ruptures immediately on contact with the target, the hazards of long ricochets are entirely eliminated and the size and location of the gunnery range becomes far less critical. The plastic 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 ac cording to the invention is provided with thermoplastic jackets l9 and 33 which also serve as a windshield to reduce aerodynamic drag of the projectile and thus minimize energy loss during flight to the target. A rotating band of plastic encircles the jacket 19 and is integral therewith for engaging the rifling in the gun bore thereby significantly 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 to the gun bore as the projectile passes therethrough. There is experimental data which indicates that barrel life in a 20 mm canon which utilizes training projectiles of the type hereinbefore described can be increased by a factor of three. Also, the plastic projectile 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 drawings and described in the foregoing specification in terms of a preferred embodiment thereof, the invention is not limited to 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 rieochets because of excellent projectile breakup on impact even at a thirty degree angle to the horizontal. I

Having thus set forth the nature of my invention, what I claim and desire to secure by Letters Patent of the United States is:

l. A plastic frangible training projectile for firing through a weapon having a rifled bore comprising a plastic jacket having an open central portion and an ogival shaped head portion, insertable disc 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.

2. The plastic frangible training projectile defined in claim 1 wherein said means within the open central portion of said projectile for controlling the center of gravity and weight of said projectile includes a plurality of disc-like platelets in face-to-face contact relationship symmetrically positioned within the open central portion of said projectile.

3. The plastic frangible training projectile defined in claim 1 wherein said means for controlling the center of gravity and weight of said projectile includes, an integral rotating band disposed around the outer surface of said plastic jacket near the rearward end thereof, a central rod-like member integral with said jacket and extending rearwardly fromthe ogival shaped head portion, a series of metal washers having central openings therein and slideably positioned over said central rodlike member, a steel pusher plate positioned in the rearward section of said jacket, said pusher plate including a short rod-like projection extending forwardly therefrom for contact with the rearward end of said central rod-like member, and a plastic end cap fixedly attached to the open rearward end of said plastic jacket against the rearward surface of said pusher plate, said plastic jacket rupturing on impact with a target thereby causing the training projectile to disintegrate immediately

Claims

1. A plastic frangible training projectile for firing through a weapon having a rifled bore comprising a plastic jacket having an open central portion and an ogival shaped head portion, insertable disc 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.

3. The plastic frangible training projectile defined in claim 1 wherein said means for controlling the center of gravity and weight of said projectile includes, an integral rotating band disposed around the outer surface of said plastic jacket near the rearward end thereof, a central rod-like member integral with said jacket and extending rearwardly from the ogival shaped head portion, a series of metal washers having central openings therein and slideably positioned over said central rod-like member, a steel pusher plate positioned in the rearward section of said jacket, said pusher plate including a short rod-like projection extending forwardly therefrom for contact with the rearward end of said central rod-like member, and a plastic end cap fixedly attached to the open rearward end of said plastic jacket against the rearward surface of said pusher plate, said plastic jacket rupturing on impact with a target thereby causing the training projectile to disintegrate immediately thereafter.