Bullet

Abstract

A plated hallow point bullet has a metallic plating which completely encapsulates a metallic core. A core precursor is formed having a nose compartment. A metallic coating is applied to the precursor to completely encapsulate the precursor. The coated precursor is mechanically deformed without breaching the coating.

Description

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to small arms ammunition, and more particularly to plated hollow point bullets particularly useful in common calibers of centerfire pistol and revolver (collectively “pistol”) ammunition.

(2) Description of the Related Art

Historically, bullets have been of all lead or of jacketed lead constructions. A variety of cartridge sizes exist which may be used in pistols, rifles or both. Among key common pistol ammunition rounds are: .380 Automatic (also commonly designated 9 mm Kurz), 9 mm Luger (also commonly designated 9×19 and 9 mm Parabellum), 0.40 Smith & Wesson (S&W), .45 Automatic (also commonly designated Automatic Colt Pistol (ACP)) and 10 mm Automatic rounds. General dimensions of and pistol rounds are disclosed in Voluntary Industry Performance Standards for Pressure and Velocity of Centerfire Pistol and Revolver Ammunition for the Use of Commercial Manufacturers ANSI/SAAMI Z299.3-1993 (American National Standards Institute, New York, N.Y.), the disclosure of which is incorporated by reference herein as if set forth at length. A newer round, the .357 Sig is also gaining acceptance.

After many decades of use of the .45 ACP round, in the 1980's the U.S. Army adopted a 9 mm Luger full ogival, pointed, full metal case or jacket (FMC or FMJ) round as the standard round for use in military sidearms (also commonly designated as M882 9 MM Luger rounds). The parameters for the M882 9 mm Luger rounds purchased by the U.S. military are shown in U.S. Military standard MIL-C-70508, the disclosure of which is incorporated by reference in its entirety herein as if set forth at length. The jacket of an FMJ round is commonly formed as a rearwardly open brass cup into which a lead core is inserted. The combination cup and core is then deformed to form the bullet ogive with the jacket rim crimped partially around the bullet base, leaving a centrally exposed portion thereof.

Similar cups may be used to manufacture JHP bullets. In some such bullets, the cup is initially rearwardly open (e.g., as in commonly owned U.S. Pat. No. 5,544,398) whereas in others the cup is forwardly open to fully encapsulate the heel of the core.

The jackets may also be electroplated. U.S. Pat. No. 5,079,814 shows a bullet wherein a lead core precursor is fully electroplated with copper to initially totally encapsulate the precursor. The combination is then deformed to create a nose compartment or cavity. The deformation involves slitting the jacket along walls of the cavity to provide weakened areas to separate petals upon impact. This process leaves exposed lead within the cavity. In other JHP manufacturing processes, a nose portion of the bullet may be masked preventing plating thereon or the plating may be removed prior to finish forming. In either of these cases, the cavity interior and perhaps a portion of the exterior of the nose will have exposed lead.

BRIEF SUMMARY OF THE INVENTION

In one aspect, I have provided a plated hollow point bullet wherein metallic plating completely encapsulates a metallic core.

In other aspects, I have invented methods of manufacturing such fully encapsulated bullets. A core precursor is formed having a nose compartment. A metallic coating is applied to the precursor to completely encapsulate the precursor. The coated precursor is mechanically deformed without breaching the metallic coating.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view of an exemplary core precursor.

FIG. 2 is a longitudinal sectional view of the precursor of FIG. 1 with a plating.

FIG. 3 is a longitudinal sectional view of the plated precursor of FIG. 2 after mechanical deformation.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

FIG. 1 shows an exemplary lead core precursor 20 for forming a 9 mm bullet. The precursor has a base or heel 22 from which a sidewall 24 extends forward. An aft portion of the sidewall 24 is substantially cylindrical and a fore portion, commonly referred to as a nose 27 of the bullet, tapers to a flattened rim 26. Inboard of the rim 26 is a nose cavity 28 having a wall 30. In this exemplary embodiment, the precursor 20 has a length L of nominally about 0.640 inch. A nominal maximum diameter D along the substantially cylindrical portion is about 0.346 inch. A nominal nose diameter D_N at an exterior of the flattened rim 26 is about 0.230 inch. The cavity has a depth of length L_C of about 0.270 inch. It should be appreciated that the core precursor 20 may be formed by swaging, casting of molten metal or another appropriate process.

FIG. 2 shows the core precursor 20 having a plating 40. The exemplary plating 40 includes an inner surface 41 and an outer surface 42 and is an about 0.005 inch thick metallic plating of, for example, copper. A nickel plating may also be used. In one embodiment, the nickel plating may be proceeded by an initial flash copper plating step. It should be appreciated that the plating 40 or coating is applied by electrolysis (e.g., electroplating), mechanical impingement plating, or the like as is known in the art.

Given the nominal thickness of the plating 40, the plated precursor 20 has a nominal maximum diameter D′ of about 0.356 inch and nominal nose diameter D_N′ of about 0.240 inch. A nominal depth L_C′ of cavity 28′ is still about the same as L_C while a nominal bullet length L′ is increased by twice the plating 40 thickness over the length L. The plating 40 is advantageously thicker than commonly used, preferably at least about 0.004 inch. To avoid compromising the mass of the bullet, the plating thickness is advantageously less than about 0.020 inch, with about 0.005–0.010 inch being preferred.

After plating, the plated core 20 is placed in a die and restruck. The restriking substantially finishes the profile of bullet, shown generally at 50 of FIG. 3, slightly reducing the maximum diameter D′ to a diameter D″ having a nominal value of about 0.355 inch. The most dramatic deformation due to the restriking is adjacent bullet nose 27′. An internal punch reforms the prior plated cavity 28′ into a final cavity 44. The restriking impresses a plurality of grooves 46 (e.g., about four or five to about eight grooves) along the interior of the cavity 44. As is generally known in the art, the grooves 46 support expansion and formation of impact petals in the bullet nose 27′ as the bullet 50 encounters soft tissue of a target (e.g., mushrooming).

In accordance with the present invention, the grooves 46 are formed in an outer surface 42′ of the plating 40 and do not penetrate an inner surface 41 ′ of the plating 40. To do this, the restriking advantageously does not expand the cavity 44, which might rupture the plating 40 due to tensile forces. The exemplary restriking advantageously compresses nose 27′, causing a slight narrowing of the cavity 44 away from the grooves 46. For example, the nose diameter D_N′ may be reduced to diameter D_N″ having a nominal value of about 0.225 inch. The exemplary restriking also shortens the depth L_C′ of cavity 44 to length L_C″ having a nominal value of about 0.250 inch and shifts the ogive/body intersection aft. In one embodiment, a thickness of the plating 40 in proximity to the grooves 46 is a minimum of about 0.004 inch and, preferably from about 0.0055 to about 0.006 inch in thickness within the cavity 44 after restriking. In one embodiment, the grooves 46 are a width of about 0.025 inch and a depth of about 0.050 inch within the cavity 44.

The bullet 50 may be loaded into a case with propellant and a primer to form a cartridge. The bullet 50 may be used alternatively, such as in a shotshell sabot or a caseless ammunition round. The total encapsulation of the lead core precursor 20 by plating 40 may provide an improved appearance and may reduce user contact with lead during handling.

One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, various different ogive and cavity shapes may be used as may be various different groove shapes and orientations. The dimensions given are merely exemplary and actual dimensions will be influenced by the particular caliber, desired bullet mass, and various form and performance considerations. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A method of manufacturing a bullet comprising: forming a core precursor having a nose cavity; applying a metallic coating onto the core precursor to completely encapsulate the precursor; and mechanically deforming the coated precursor to reduce the nose diameter of the precursor and the inner diameter of the nose cavity in the precursor, and to form plurality of indentations within the nose cavity without breaching or rupturing the coating.

2. The method of claim 1 wherein: the forming comprises swaging; the applying comprises electroplating; and the mechanically deforming comprises impacting the metallic coating of the nose cavity with a tool to form a plurality of indentations extending at least mostly longitudinally so as to define locally weakened areas for defining impact petals.

3. The method of claim 2 wherein the deforming does not penetrate the metallic coating of the nose cavity.

4. The method of claim 2 wherein the deforming decreases the depth of the nose cavity.

5. The method of claim 1 wherein: the forming comprises forming said nose cavity with a first depth of at least 0.20 inch; and the deforming produces a bullet nose cavity of a second depth less than the first depth.

6. The method of claim 1 wherein the deforming produces a bullet nose cavity of 0.15–0.35 inch.

7. The method of claim 1 wherein: the forming comprises forming said precursor nose with a first diameter at a rim thereof; the applying produces a coated precursor nose with a second diameter at a rim thereof greater than the first diameter; and the deforming produces a bullet nose with a third diameter at a rim thereof less than the second diameter.

8. The method of claim 1 wherein the third diameter is less than the first diameter.

9. The method of claim 1 wherein the deforming compresses the nose diameter of the precursor by at least 0.010 inches.

10. The method of claim 9 wherein the deforming comprises compressing the nose of the precursor to cause a slight narrowing of the nose cavity's inner diameter, such that the forming of the plurality of indentations does not result in expansion of the nose cavity and coating that would cause a rupture in the coating.

11. The method of claim 10 wherein the deforming forms a plurality of indentations extending at least mostly longitudinally so as to define locally weakened areas for defining impact petals.

12. The method of claim 11 wherein the plurality of indentations comprise grooves having a width of about 0.025 inches and a depth of about 0.050 inches.

13. A method of manufacturing a bullet comprising: forming a core precursor having a nose cavity;applying a metallic coating onto the core precursor to completely encapsulate the precursor; andmechanically deforming the coated precursor to reduce the nose diameter of the precursor by at least 0.010 inches and cause a slight narrowing of the nose cavity's inner diameter such that the deforming may further form a plurality of indentations within the nose cavity that does not result in expansion of the nose cavity and coating that would cause a rupture or penetration of the coating, wherein the plurality of indentations extend at least mostly longitudinally so as to define locally weakened areas for defining impact petals.