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:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This patent application claims priority to U.S. Provisional Patent Application Serial No. 60/361,658, entitled “BULLET” that was filed on Mar. 4, 2002, the disclosure of which is incorporated by reference in its entirety herein as if set forth at length. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    (1) Field of the Invention  
           [0003]    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.  
           [0004]    (2) Description of the Related Art  
           [0005]    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: 0.380 Automatic (also commonly designated 9 mm Kurz), 9 mm Luger (also commonly designated 9×19 and 9 mm Parabellum), 0.40 Smith &amp; Wesson (S&amp;W), 0.45 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 0.357 Sig is also gaining acceptance.  
           [0006]    After many decades of use of the 0.45 ACP round, in the 1980&#39;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 9MM 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.  
           [0007]    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.  
           [0008]    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  
         [0009]    In one aspect, I have provided a plated hollow point bullet wherein metallic plating completely encapsulates a metallic core.  
           [0010]    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.  
           [0011]    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  
       [0012]    [0012]FIG. 1 is a longitudinal sectional view of an exemplary core precursor.  
         [0013]    [0013]FIG. 2 is a longitudinal sectional view of the precursor of FIG. 1 with a plating.  
         [0014]    [0014]FIG. 3 is a longitudinal sectional view of the plated precursor of FIG. 2 after mechanical deformation. 
     
    
       [0015]    Like reference numbers and designations in the various drawings indicate like elements.  
       DETAILED DESCRIPTION  
       [0016]    [0016]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.  
         [0017]    [0017]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.  
         [0018]    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.  
         [0019]    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).  
         [0020]    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 .  
         [0021]    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.  
         [0022]    One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications maybe 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.