US3780657A

US3780657A - Frangible projectile

Info

Publication number: US3780657A
Application number: US00183967A
Authority: US
Inventors: M Zaid
Original assignee: Colts Inc
Current assignee: CFPI Inc A CORP OF; COLT LICENSING A DE Ltd PARTNERSHIP LP; CII Holdings Inc
Priority date: 1971-09-27
Filing date: 1971-09-27
Publication date: 1973-12-25
Anticipated expiration: 1990-12-25

Abstract

A bullet assembly with a projectile body formed of a low mass frangible material lethal over a limited effective range and which may be provided with an obturator between the projectile body and a propellant charge.

Description

10s Mei 1191 Zaid 1 Dec. 25, 1973 FRANGIBLE PROJECTILE 3.060.856 10/1962 Dunn 102/41 3.137.195 6/1964 Rosenberg, Jr.... 102/95 X [75] Invenmn Melvm Old westbury, 3.326.133 6/1967 Sladlefet al 102/927 73 Assigneez COWS Inc, Hartford Conn 463,528 11/1891 Mieg l 1. 102/41 3.062,l45 11/1962 Morgan et a1. 1. 102/38 [22] Filed: Sept. 27, 1971 [21] Appl. No.2 183,967 Primary Examiner-Robert F. Stahl Attorney-Prutzman, Hayes, Kalb & Chilton [52] US. Cl. 102/41, 102/927 [51] Int. Cl. F42b 5/22, F42b 11/38 [57] ABSTRACT [58] Field of Search l02/921.(7):2/49l3, 3985, A bullet assembly with a projectile y formed of a low mass frangilbe material lethal over a limited effec- [56] References Cited tive range and which may be provided with an obturath t'l b d d 11 t UNTED STATES PATENTS grarlgazlween e PIOJEC 1e 0 y an a prope an 3.598.058 8/1971 Smith 102/41 3,650,213 3/1972 Abbott et al 102/92.7 10 Claims, 5 Drawing Figures if M PATENIEDUEEZSIBH 3,780, 657

sum 1 or 2 FIG. 3 w w INVENTOR MELVIN ZAID ATTORNEYS FRANGIBLE PROJECTKLE This invention generally relates to limited lethality ammunition and particularly concerns frangible projectiles.

Known frangible projectiles have heretofore been directed to types used for practice purposes, which would normally break up immediately after leaving the muzzle, or those types used in target or shooting galleries, which disintegrate harmlessly upon target impact. Recent efforts have been directed to providing a different type ammunition having a projectile fully lethal for a limited range. Experimentation with frangible bullets utilizing a variety of materials and powder charges over different ranges has resulted in a continuing effort to provide satisfactory projectile frangibility while also establishing a limited effective range throughout which the projectile is lethal for specific applications, for example, riot control and similar purposes such as antihijacking. Such applications require significant damage to live targets and subsequent breakup into harmless pieces after impact with and penetration of the projectile into the target while additionally requiring that the projectile be non-lethal beyond a specified range for use in close quarters, such as in aircraft.

Accordingly, a primary object of this invention is to provide a new and improved projectile which will serve seemingly incompatible objectives of being fully lethal over an established limited effective range and also break-up upon impact to minimize any second target damage.

Another object of this invention is to provide a frangible projectile of the above-described type particularly suited for low cost manufacture.

A further object of this invention is to provide an improved frangible bullet assembly particularly suited for use in different types of projectile containers such as a standard cartridge case or a disposable revolver cylinder. Included in this object is the aim of providing such a bullet assembly having a novel obturator for effecting spin velocity to the projectile mass and also affording it shock relief when fired.

Other objects will be in part obvious and in part pointed out in more detail hereinafter.

A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the following detailed description and accompanying drawings which set forth certain illustrative embodiments and are indicative of the various ways in which the principle of the invention is employed.

In the drawings:

FIG. 1 is a schematic view of a gun barrel and firing mechanism suitable for use with this invention;

FIG. 2 is a longitudinal side view, partly broken away and partly in section, showing one embodiment of a limited lethality projectile within a standard cartridge case;

FIG. 3 is a fragmentary longitudinal cross sectional view, partly broken away, of another embodiment of a limited lethality projectile within a disposable revolver cylinder;

FIG. 4 is a graph showing a muzzle velocity band and range relationships for a projectile of this invention; and

FIG. 5 is a graph showing muzzle velocity and lethal range relationships for a projectile of this invention.

Referring to the drawings in detail, a conventional cartridge case 10, e.g., a 0.38 caliber cartridge case fabricated from suitable material such as brass is shown in FIG. 2 with a projectile l2 fitted within an open end of the cartridge case 10. A propellant or powder chamber 14, located rearwardly of the projectile l2 and forwardly ofa closed rear end 16 of the cartridge case 10, is partially filled with a conventional propellant 18. A primer 20 is centrally located in a rear face of the closed rear end 16 of the cartridge case 10. The primer 20 may be a standard percussion sensitive type which detonates upon being struck by a firing pin, such as at 22 of a revolver 24 illustrated in FIG. 1, and shock wave and flame exits through a passageway 26 to ignite the propellant 18 and cause substantially instantaneous expansion of the byproducts of combustion to expel the projectile 12 from a barrel 28 of the revolver 24.

A typical 0.38 caliber projectile such as a standard lead bullet possesses a muzzle velocity of about 850 feet per second and will have an effective standard projectile range of approximately 1,200 feet. While the actual range is greater than 1,200 feet, for purposes of this description, that range wherein there is lethal stopping or hitting power is considered to be the effective range.

To obtain lethal hitting power over a limited effective range in accordance with this invention, the projectile 12 comprises a body formed of a solid nonmetallic frangible material which fragmentizes upon impact and which has a low mass density relative to that of a standard lead bullet, to desirably limit the range of the projectile 12 to a first distance of travel which is well short of the normal range of a standard lead bullet fired at the same muzzle velocity. More specifically, the material of the projectile 12 is a cementitious material of substantially uniform density throughout the projectile mass, and the propellant 18 selected is one which would have sufficient force to impart at least lethal velocity over a preselected range which is herein referred to as a first distance of travel. That is, should the projectile l2 strike a kidney, heart or other major organ of an animal body over such first distance, the impact would be fatal to the animal. Such results are virtually ensured by the frangibility characteristics of the projectile 12. The frangibility of the projectile 2 is chosen to effect a wound cavity of significantly amplified size relative to the size of the projectile body before fragmentation, and fragmentation effects an invaluable advantage in minimizing second target damage when used, for example, in riot control. Fragmentation to a powdery substance upon target impact is not sought, although this result may well occur upon impact of the projectile 12 with a hard metal surface such as sheet aluminum, for example, within the confines of an aircraft. Rather, the type of fragmentation sought is that which throughout a predetermined limited lethal range (or first distance of travel) will result in break-up of the projectile body upon impact with endoskeletal animal flesh. A broad spectrum of different lethality levels at preselected muzzle velocities and strike distances has been found by testing various frangible projectiles formed by the mixing of different cementitious materials. Experimentation has also been conducted under similar controlled conditions with weapons having both smooth bore and rifled barrels. Based on such experiments, it is believed that the lethality level is significantly higher when a spin velocity is imparted to the frangible projectile 12.

To provide such projectile spin, a barrier means or obturating wad 30 is located within the case between the propellant 18 and the projectile body 12 to distribute propelling forces over the entire rear face of the projectile body 12 while preserving its integrity upon being fired from a gun, in addition to imparting desired spin velocity to the projectile body 12. In the specifically illustrated embodiment of this invention shown in FIG. 2, the wad 30 is preferably a sleeve formed of suitable plastic material and having an interior dividing wall 32 located midway between opposite open ends of the sleeve providing a pair of cup-shaped end portions facing in opposite axial directions. The forwardly facing cup-shaped end portion receives a correspondingly shaped reduced rear end portion 34 of the projectile body. The cup-shaped rear end portion of the wad 30 is accordingly formed with a recess 36 facing the powder chamber 14 with a circumferentially extending wall 38 surrounding the recess. The wall 38 is deformable radially outwardly upon ignition of the propellant 18 in the powder chamber 14 thereby to engage rifling lands such as at 40 within the gun barrel 28 for imparting the desired spin velocity to the frangible projectile 12.

Cementitious material generally includes any substance for making bodies adhere to each other such as asphalt, glue, gypsum, lime, paste, plaster of Paris, Portland cement, tar and similar substances. Specific compositions of the frangible projectile bodies of this invention have been made of cement and plaster.

Cement is basically a finely powdered mixture oflime and earth clay or impure calcium aluminum silicate. Portland cement is composed of a complex calcium aluminum silicate. As with plaster, additives can be introduced into the mix, such as gypsum to retard setting, and aggregates may be added for strength and economy. Typical aggregates varying in size include crushed marble, white quartz, granite, gravel, marble dust, silica flour, fine sand, and talc.

The parent mineral of plaster is gypsum which is found in several forms: alabaster (a massive variety of gypsum), white spar or satin spar (a fibrous variety of gypsum), selenite (a crystalline form of the mineral). Gypsum is occasionally referred to as hydrated sulphate of lime, hydrated calcium sulphate and, chemically, CaSO -2H O. Plaster is also known as CaSO 1/2H O, sulphate of lime, hemihydrate of calcium sulphate, castin gp last er, gypsum plaster, and dental plaster, in addition to specific trade names.

Generic names of plaster are alpha gypsum plaster, alpha hemihydrate of calcium sulphate, beta hemihydrate of calcium sulphate. The alph and beta are different crystalline structures; the alpha hemihydrate of calcium sulphate being sold under the trademark Hydro' cal," and the beta hemihydrate of calcium sulphate being normal plaster. The alpha version can be made more dense; thereby demanding less water.

Numerous commercially available additives (up to 42 according to one manufacturer) may be included in the plaster mix with each additive providing some control on expansion, set, strength, flow, water use, etc. These additives include sulphates as accelerators; commercial retarding agents such as borax, carpenters glue, calcined lime, powdered marshmallow roots, alcohol, sugar and citric or acetic acid; hardeners such as lime, magnesium fluosilicate, white dextrine or gum arabic, and white Portland cement; binding materials such as long and short-fibered. asbestos, ordinary white absorbent cotton, sisel or hemp, and animal hair. Specific proportions of each additive is normally treated as proprietary information by each manufacturer.

In different plaster mixtures, different levels of lethality have been obtained. Two specific examples, which perhaps may be preferred, are mixtures of water with the previously mentioned Hydrocal plaster and a plaster of Paris sold under the trademark Red-Top.

For example, a total 18 grain mixture, 67 percent Red-Top plaster of Paris and 33 percent water by weight, was mixed for 15 to 20 seconds after adding the plaster to the water in a plastic beaker. The mix was then poured into molds (not shown) each of which contained a plastic wad 30. After being leveled off, the molds were cured in a 60 C. oven for two hours. The projectiles were then ejected from the molds and inserted into standard 0.38 caliber cartridge cases, such as at 10, loaded with three grains of propellant sold under the trademark Bullseye. The volume of each cartridge case after insertion of a plaster round and wad was 0.028 cubic inches giving a loading density of 0.015 pound per cubic inch in all cases.

The same procedure was utilized in making Hydrocal plaster bullet assemblies except that a 19 grain mixture of 67 percent Hydrocal-plaster and 33 percentwater was used.

In actual tests utilizing a 0.38 caliber revolver having a two inch rifled barrel, an average strike velocity of about 900 and 1,100 feet per second was obtained respectively at ranges of about 8 feet and 4 feet from muzzle to target. The Red-Top bullet assembly resulted in large volume muscle wounds although no significant residual velocity of the projectile was observed after bone impact. While it appeared from such tests that the Red-Top bullet assembly can destroy ribs and muscles, the bullet assembly did not appear to have sufficient penetrating capability to affect internal organs after penetrating clothing and breaking bone. At the tested ranges and strike velocities, no penetration of 40 mil thickness aluminum sheet occurred.

A 19 grain Hydrocal plaster projectile provided full penetration of 40 mil aluminum sheet at a strike velocity of approximately 1,200 feet per second at about 4 foot range and less. This projectile also fully penetrated bone with sufficient velocity to inflict mortal damage on major organs and blood vessels over a short range of 6-8 feet with strike velocities of about 1,000 fps while being nonlethal beyond about 10 feet. When striking an array of 1 inch pine boards at a short range of about 6 to 8 feet away in which the boards were separated by air space, 'only the first board was penetrated by the Hydrocal rounds, and the second board received only plaster dust and sustained no damage. These characteristics exhibited by Hydrocal" rounds should prove to be exceedingly valuable when double plexiglas aircraft cabin windows and hardboard-backed aluminum sheet is struck by such a frangible projectile.

All Red-Top and Hydrocal projectiles were found to have penetrated tissue without exiting and to have opened up a wound cavity many times the size of the projectile body. Each projectile upon recovery was also found to be broken into one-fourth inch and smaller diameter pieces. It is believed that the effect of the projectile pieces traveling outwardly from the wound tract due to spin velocity accounts for the increased wound volume of the projectiles, and this concept appears to be substantiated by a slightly reduced wound volume found for more cohesive I-Iydrocal plaster mix. It was also noted that nondeformable metallic projectiles, such as aluminum having the same mass as the plaster projectiles, do not break up when fired at the same muzzle velocities and did virtually no tissue damage. Aluminum projectiles, of twice the mass of the frangible projectiles, yield wounds of low volume similar to those inflicted by standard lead bullets.

'The relatively low mass density of the projectile l2 and its cohesive strength are preselected to ensure that upon impact and penetration of endoskeletal animal flesh over the first lethal distance of travel of the projectile, the projectile 112 will possess a sufficiently high velocity to effect a lethal striking velocity despite the high velocity drop-off due to the low mass of the projectile 12 and the high frictional atmospheric drag imparted thereon before impact.

Velocity drop-off with range of the described Red- Top'bullet assembly is presented in FIG. 4! for a selected muzzle velocity band. Muzzle velocity can be increased by changing the propellant mix, the quantity of the propellant and/or the barrel length. While the subject of lethality is not subject to precise definition, nonetheless, to evaluate lethal range of a selected muzzle velocity, the muzzle velocity required at any specific range is calculated to obtain the lethal striking velocity and the propellant loading is adjusted to obtain such muzzle velocity. Any lethality effects due to change in mass have to be evaluated experimentally since standard lethality tables do not exist at this time for frangible projectiles or for additives to the cementitious mix. The above described Red-Top plaster rounds appear lethal for strike velocities greater than about 700 feet per second. superimposing this approximate lethal limit onto FIG. 4, lethal and nonlethal ranges for this band of muzzle velocities are defined. The lethal range" versus muzzle velocity for Red- Top plaster rounds can be obtained directly from FIG. 4 and the results are presented in FIG. 5 which is a graph showing typical muzzle velocity and lethal range relationships for such a Red-Top plaster projectile.

To further increase the lethality of the round, muzzle velocity may be increased, weight increasing additives such as shot and similar substances may be included that can be held together in a plaster matrix, and/or the projectile mass density may be increased.

The utilization of the inventive concept of this invention, while ideally suited for incorporation into standard cartridge cases, is additionally useful in other applications. For example, a disposable cylinder is shown in FIG. 3 ofa type fully described in my US. Pat. application Ser. No. 104,603 entitled Improved Cylinder for Revolvers filed Jan. 7, 1971, assigned to the assignee of this invention, the subject matter of this application being incorporated herein by reference. In FIG. 3 the same numbers as in FIG. 2, increased by 100, are used to identify like parts. The modified form of the invention illustrated in FIG. 3 shows a projectile body 112 provided in a disposable cylinder 140 to be fired from a suitable weapon such as the revolver 24. The loading of the projectile 1 12 is substantially identical to that previously described in connection with the projectile l2 fitted in the standard cartridge case 10. After being loaded into the disposable cylinder 140, each round M2 is preferably sealed with a protective coating 142 which may be a brushable one part, thixotropic compound which air dries to a tough, rubbery protective film.

A frangible projectile constructed in accordance with this invention will provide a limited lethality range for a selected band of muzzle velocities and is desirably non-lethal beyond such a range to meet needs for such ammunition in close quarters for effecting significant damage while retaining frangibility. In addition, the projectiles of this invention are particularly useful in connection with both a standard cartridge case and a disposable cylinder and in either event may be quickly and easily mass produced at low cost.

As will be apparent to persons skiiled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

I claim:

I. A bullet assembly suitable for being propelled from a gun barrel having rifling lands and grooves formed therein and comprising a projectile, a container, a propellant received in the container and having sufficient force to impart at least a lethal striking velocity to the projectile over a first distance of travel, and an obturating wad disposed between the propellant and the projectile with the wad engaging a trailing end portion of the projectile, the obturating wad being engageable with the rifling lands to impart a spin velocity to the projectile upon its being fired from the gun and additionally effecting combustion gas sealing within the barrel during exit of the projectile therefrom, the projectile being formed ofa solid nonmetallic cementitious material which is fragmentizable and of low mass density, relative to a standard metallic projectile, the projectile mass having substantial uniformity throughout and being of sufficiently low mass density to limit travel of the projectile to a total distance of travel greater than said first lethal distance of travel but less than a predetermined standard projectile range of a standard metallic projectile fired from a gun at the same muzzle velocity.

2. The bullet assembly of claim I wherein the container is a standard cartridge case with the projectile received at least in part within the case.

3. The bullet assembly of claim 1 wherein the obturating wad distributes the propelling forces over a rear face of the projectile.

4. The bullet assembly of claim 1 wherein the projectile is a solid homogeneous mass.

5. The bullet assembly of claim 1 wherein the barrier means comprises an obturating wad fixed to said one of the projectile on a trailing end portion thereof.

6. The bullet assembly of claim 1 wherein the obturating wad is fixed to a trailing end portion of the projectile.

7. The bullet assembly of claim I further including protective sealing means covering exposed portions of the projectile.

8. The bullet assembly of claim 1 wherein the solid material of the projectile is of a mass density and cohesive strength sufficiently low to fragmentize upon impact without penetration of 40 mil thickness aluminum sheet at a distance of ten feet and beyond.

9. The bullet assembly of claim 1 wherein the mass density and cohesive strength of the projectile is sufficiently high to penetrate endoskeletal animal flesh over 8 ing radially outwardly deformable wall cooperating with the rearward end of the cartridge case to define a chamber therein receiving the propellant, the radially outwardly deformable wall of the obturating wad providing gas sealing of the products of combustion upon ignition of the propellant in addition to preserving the integrity of the projectile upon its being fired from the gun.

Claims

1. A bullet assembly suitable for being propelled from a gun barrel having rifling lands and grooves formed therein and comprising a projectile, a container, a propellant received in the container and having sufficient force to impart at least a lethal striking velocity to the projectilE over a first distance of travel, and an obturating wad disposed between the propellant and the projectile with the wad engaging a trailing end portion of the projectile, the obturating wad being engageable with the rifling lands to impart a spin velocity to the projectile upon its being fired from the gun and additionally effecting combustion gas sealing within the barrel during exit of the projectile therefrom, the projectile being formed of a solid nonmetallic cementitious material which is fragmentizable and of low mass density, relative to a standard metallic projectile, the projectile mass having substantial uniformity throughout and being of sufficiently low mass density to limit travel of the projectile to a total distance of travel greater than said first lethal distance of travel but less than a predetermined standard projectile range of a standard metallic projectile fired from a gun at the same muzzle velocity.

2. The bullet assembly of claim 1 wherein the container is a standard cartridge case with the projectile received at least in part within the case.

7. The bullet assembly of claim 1 further including protective sealing means covering exposed portions of the projectile.

9. The bullet assembly of claim 1 wherein the mass density and cohesive strength of the projectile is sufficiently high to penetrate endoskeletal animal flesh over said first distance of travel while yet being fragmentizable upon entry therein.

10. The bullet assembly of claim 1 wherein the container includes a generally tubular cartridge case closed at a rearward end thereof, the projectile being of a generally cylindrical shape received in the cartridge case and closing an open forward end thereof, and wherein the barrier means includes an obturating wad fixed on a trailing end portion of the projectile, the obturating wad having a rearwardly facing recess and a surrounding radially outwardly deformable wall cooperating with the rearward end of the cartridge case to define a chamber therein receiving the propellant, the radially outwardly deformable wall of the obturating wad providing gas sealing of the products of combustion upon ignition of the propellant in addition to preserving the integrity of the projectile upon its being fired from the gun.