US3245349A

US3245349A - Safety type bullets

Info

Publication number: US3245349A
Application number: US359647A
Authority: US
Inventors: Kerr Raymond William
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-04-14
Filing date: 1964-04-14
Publication date: 1966-04-12
Anticipated expiration: 1983-04-12

Description

April 12, 1966 R. w. KERR 3,245,349

SAFETY TYPE BULLETS Filed April 14, 1964 INVENTOR.

United States Patent Ofi ice 3,245,349 Patented Apr. 12, 1966 3,245,349 SAFETY TYPE BULLETS Raymond William Kerr, Box 4178, Lincoln, Nebr. Filed Apr. 14, 1964, Ser. No. 359,647 3 Claims. (Cl. 102-41) The present invention relates to small arms ammunition and more particularly to such ammunition of the safety type intended primarily for practice range use.

Practice ammunition of the type having both a case and a projectile of plastic material has previously been proposed (US. Patent No. 3,060,856 to Dunn). Such ammunition has proved to be economical to use. However, its safety and accuracy permit of improvement. Commercially available ammunition of this type have been provided with a relatively hard plastic projectile which has been found to possess substantial penetration when fired. Indeed, it has been found that at firing distances on the order of twenty-five feet such projectiles consistently penetrate into wood a distance of approximately one-quarter inch. In addition their momentum upon being fired has resulted in undesirable bounce back. These prior practice rounds using lightweight projectiles and reduced charges etfect projectile travel at reduced velocity but at the expense of accuracy. The primary reason is apparently that the projectiles tumble and float during flight and thus do not have the necessary flat trajectory required to test or improve a marksmans accuracy.

It is a general object of the present invention to provide practice ammunition which maintains the advantages of economy and reusability of prior forms, and which is substantially improved from the standpoints of safety and accuracy in use.

It is a more specific object of the invention to provide practice safety ammunition which is economical to manufacture and can be reused after firing and which incorporates a stabilized projectile which effects accurate flight yet which can be readily formed of resilient and relatively lightweight material.

It is a further object to provide practice ammunition which not only can be used in standard firearms, but which is substantially improved from the standpoint of safety so that the hazards that are ordinarily encountered in using guns for practice purposes are minimized.

Other objects and advantages of the invention will become apparent from the following description and upon reference to the accompanying drawings, in which:

FIGURE 1 is an elevational view of a round of safety ammunition embodying the present invention as received within the firing chamber of a firearm which is fragmentarily illustated.

FIG. 2 is a side elevation, partly in section, of the cartridge casing;

FIG. 3 is a side elevation of a projectile fashioned according to the present invention;

FIG. 4 is a rear elevation of the cartridge casing of FIG. 2 showing a primer in place therein;

FIG. 5 is a rear end elevation of the projectile of FIG. 3;

FIG. 6 is a side elevation of an alternative embodiment of the projectile shown in a cartridge casing which is shown in section; and

FIG. 7 is a front end elevation of the projectile of FIG. 6.

While the invention is described in connection with certain preferred embodiments, it will be understood that it is not thereby intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Referring more particularly to FIGS. 1-5 of the drawinng, safety ammunition embodying the present invention is there shown in the form of a round 10. The round 10 includes a cartridge casing 11 having a central cavity 12 extending longitudinally through the casing between its opposite

open ends

14, 15. The casing 11 is complementally formed to fit into a firing chamber 16 of a firearm 17. The firing chamber along with a firing mechanism, generally indicated at 18, are disposed at the rear of a barrel 19. Inserted snugly into forward end 14 of the casing 11 is a projectile 20 having a generally cylindrical body 21 which terminates at its forward end in a blunt nose 22. A primer 23 is provided to provide propelling force for the projectile 20 and is thus fitted into the rear end 15 of the casing closing that end of the cavity 12.

For firing the round 10 and propelling the projectile through the barrel 19, the primer 23 is detonated when its exposed end 24 is struck by a firing pin 25 of the mechanism 18. The explosive force of the gases produced from detonating the primer is increased by providing a venturi effect resulting when the gases pass through intermediate cavity portion 26 which is of substantially reduced diameter, and blast into the larger diameter projectile-receiving forward portion of the cavity 12. For containing the explosion and direction the gas force into and through the venturi 26, the defining wall portions of the cartridge casing are thicker adjacent its rear end 15. At its rear end, so as to hold the round 10 in position for firing within the firing chamber 16 and also to facilitate removal of the cartridge casing after the round has been fired, the

casing is provided with an integral peripheral lip or shoulder 28. I

In accordance with the present invention, a round of safety ammunition for practice use in a firearm is provided which incorporates a lightweight projectile and low firing power primer contributing to effect reduced momentum of the projectile as compared to conventional heavy weight projectiles and thereby reduce the penetrative ability of the projectile while providing stabilizing means on the projectile for substantially effecting the accuracy ordinarily obtainable only with the heavier projectiles. In the present instance the projectile 20, which is preferably formed of resilient, relatively lightweight material, is snugly fitted into the forward end 14 of the cartridge casing 11 closing it. The projectile includes stabilizing means which as shown is in the form of a plurality of longitudinally disposed, radially projecting fins 29, 30, 31, 32. The fins extend rearwardly from the projectile's generally cylindrical body 21, and are normally received in the forward end of the cartridge cavity 12. The

fins

29, 30, 31, 32 are symmetrically disposed about the longitudinal axis of the projectile, and the radial extension of the fins is limited so that they can be fitted into the cartridge cavity 12 without distortion. For concentrating the drag toward the rear of the projectile and thereby aerodynamically stabilizing it, the fins increase in radial dimension rearwardly. This gives the projectile fins a rearwardly flared profile. The fins are relatively thin so that the center of mass of the projectile is forwardly located. 1 By fashioning the projectile of a lightweight material such as plastic, rubber, paper, wood, aluminum or the like, a small primer can be used instead of the larger and more powerful primer and/or powder charge which is necessary for heavier weight projectile constructed of hard plastics, steel, lead and the like. Furthermore, even using lightweight materials the overall projectile weight necessary for accurate flight is less than that of reusable plastice projectiles heretofore available.

' As has been described, the primer 23 and projectile 20 fit respectively into the

casing ends

14, 15 to close the cavity 12. Accordingly, when the primer 23 is detonated, the resulting propelling gases are directed along the fins and against the rear surface 34 of the projectile body 21 so as to propel it through the firearm barrel 19. Because of the lighter weight projectile a smaller primer, in practice a No. 1% primer as compared to a 2 /2 primer, can be used in cartridges according to the present invention as compared to devices of the prior art which use heavier and less stable projectiles. Of course, it is an overall consideration in selecting the weight of the projectile and the size of the primer that sufficient velocity must be provided to propel the projectile on a substantially flat projeetory over target range distances. But by severely reducing the weight and velocity of the projectile, its momentum (mass x velocity) is also reduced. The stabilizing means guide the projectile so that it travels accurately to the target at which the firearm is aimed. By reducing the momentum the dangers of a penetrating projectile as well as of a bouncing back projectile are greatly reduced.

By reducing the muzzle velocity of the projectile it can be made even safer in use. This result can be achieved by permitting a portion of the force created by the explosive gases of the detonated primer to dissipate. To this end, an alternative embodiment of projectile 20a, constructed in accordance with the present invention, is shown in FIGS. 6 and 7, wherein the body portion 21a of the projectile is provided with

longitudinal grooves

38, 39, 40, 41 spaced about the periphery of the body portion 21a. The

grooves

38, 39, 40, 41 provide for the partial escape, between the projectile body portion 21a and the casing wall 35, of the explosive gases that are directed at the rear surfaces 34a of the projectile body 21a succeeding detonation of the primer. Thus, the projectile is delivered from the firearm barrel at a reduced velocity and therefore at a lower momentum so as to enhance the safeness in use.

It has been found that to avoid impairing accuracy of flight, using a lighter weight and a lower propulsion velocity for the projectile, it is desirable to extend the length of the fins 29a, 30a, 31a 32a of the alternative embodiment as shown in FIG. 6. Thus, the drag effected by the fins is concentrated further rearward of the projectile body portion 21a.

Another feature of the present invention exemplified in the alternative embodiment lies in providing an easily achieved snug fit of the projectile even after repeated use. To this end, adjacent its rear end, the rear portion of the peripheral surface of the body portion 21a is inclined toward the projectile axis from front to rear as indicated at 42. This constructive feature together with that of providing the projectile body portion with a maximum diameter slightly greater than that of the cavity 12 at the casing front end 14, assures a snug fit of the projectile body within the front end of the casing.

It has been found in practice using the small primer and lightweight projectiles that the velocity of the projectiles has been reduced from approximately 500 feet per second to approximately 300 feet per second. Projectiles as low in weight as 7 /2 grains have been used successfully as compared with a 14 /2 grain weight of previously available reusable plastic projectiles.

In comparative tests of penetration, it has been found in practice that improved safety ammunition embodying the present invention when fired at a paraflin block from a distance of 20 feet has barely dented it, penetration being only on the order of .010 to .015 of an inch. Ammunition of the prior art fired under identical conditions consistently penetrated the same paraflin block approximately .250 to .310 of an inch.

The instant safety ammunition can be fired through a rifled barrel or a smooth bore barrel with equal accuracy. The velocity of the projectile appears to be further reduced by rifling, and thus the safety properties of the ammunition are further enhanced.

I claim as my invention:

\ 1. A round of safety ammunition for practice use in a firearm having a barrel and having a firing mechanism and a firing chamber disposed at one end of the barrel, said round comprising, in combination, a cartridge casing complementally formed for reception in the firing chamber, said casing having a central cavity extending longitudinally therethrough, a plastic bullet of relatively lightweight plastic material having a generally cylindrical body shaped to fit snugly into one end of said casing closing said cavity at that end, said body terminating at its forward end in a blunt nose and at its trailing end in a plurality of radially projecting fins symmetrically disposed about the longitudinal axis of the plastic bullet, and a propellant consisting entirely of a primer fitted snugly into the opposite end of said casing and closing said cavity at that end, which primer is responsive to striking by the firing mechanism to explode and propel said plastic bullet through the barrel with said fins stabilizing said bullet against tumbling in flight.

2. A plastic bullet for use in safety ammunition having a cartridge casing complement'ally formed for reception in a firing chamber and a longitudinal cavity extending through the casing with a primer inserted into one casing end, said bullet being formed of lightweight resilient plastic material having a generally cylindrical body portion for reception snugly in the forward end of the casing and having a plurality of rearwardly extending tail fins secured at their forward ends to said body and disposed in symmetrically spaced relation about the longitudinal axis of the bullet and of increasing radial extent from their forward toward their rear ends for stabilizing said plastic bullet in flight against tumbling, said body portion having an intermediate transaxial diameter slightly larger than that of the casing cavity and tapering to a slightly lesser diameter at its rear end so as to facilitate insertion of the plastic bullet into the casing.

3. A projectile for use in a round of safety ammunition which round includes a cartridge casing having a longitudinal cavity extending therethrough with a primer disposed at the rear end of the cavity, said projectile being formed of lightweight resilient material with a body portion for reception in the forward end of the casing and a plurality of symmetrically spaced tail fins extending rearwardly from said body portion for stabilizing said projectile in flight, said body portion having longitudinal grooves formed in its peripheral surface for partially dissipating the expulsion force resulting from the detonation of the primer so as to reduce the velocity at which said projectile is propelled.

References Cited by the Examiner UNITED STATES PATENTS 1,601,885 10/1926 Samsel 10250 X 1,611,431 12/1926 Froelich l02-51 X 2,494,026 l/l950 Anderson 102-50 2,573,362 10/1951 Rouse 102--38 2,872,864 2/1959 Barnes et a1. 102-38 3,060,856 10/1962 Dunn 10241 3,157,126 11/1964 Blondeau 10238 X BENJAMIN A. BORCHELT, Primary Examiner.

R. F. STAHL, Assistant Examiner.

Claims

1. A ROUND OF SAFETY AMMUNITION FOR PRACTICE USE IN A FIREARM HAVING A BARREL AND HAVING A FIRING MECHANISM AND A FIRING CHAMBER DISPOSED AT ONE END OF THE BARREL, SAID ROUND COMPRISING, IN COMBINATION, A CARTRIDGE CASING COMPLEMENTALLY FORMED FOR RECEPTION IN THE FIRING CHAMBER, SAID CASING HAVING A CENTRAL CAVITY EXTENDING LONGITUDINALLY THERETHROUGH, A PLASTIC BULLET OF RELATIVELY LIGHTWEIGHT PLASTIC MATERIAL HAVING A GENERALLY CYLINDRICAL BODY SHAPED TO FIT SNUGLY INTO ONE END OF SAID CASING CLOSING SAID CAVITY AT THAT END, SAID BODY TERMINATING AT ITS FORWARD END IN A BLUNT NOSE AND AT ITS TRAILING END IN A PLURALITY OF RADIALLY PROJECTING FINS SYMMETRICALLY DISPOSED ABOUT THE LONGITUDINAL AXIS OF THE PLASTIC BULLET, AND A PROPELLANT CONSISTING ENTIRELY OF A PRIMER FITTED SNUGLY INTO THE OPPOSITE END OF SAID CASING AND CLOSING SAID CAVITY AT THAT END, WHICH PRIMER IS RESPONSIVE TO STRIKING BY THE FIRING MECHANISM TO EXPLODE AND PROPEL SAID PLASTIC BULLET THROUGH THE BARREL WITH SAID FINS STABILIZING SAID BULLET AGAINST TUMBING IN FLIGHT.