5.56 Small arms ammunition

Abstract

Described herein is a round of ammunition for firing from a gun having a rifled barrel, especially a small arms weapon. The round comprises a body core ( 7 ) which has a plurality of knurl lines ( 9 ) and associated grooves ( 6 ) formed over a portion of the body core ( 7 ). Jacket material ( 11 ) is provided over the body core ( 7 ) such that the inner diameter ( 10 ) of the jacket material ( 11 ) makes contact with the knurl lines ( 9 ). During firing of the round, the jacket material ( 11 ) deforms into the grooves ( 6 ) formed between the knurl lines ( 9 ) enabling the rifle engraving to take place with a substantially reduced axial force.

1 . The combination of a gun having a rifled barrel and a round of ammunition; the rifling of the barrel comprising rifling grooves which are separated by lands extending helically along the length of the barrel; the round of ammunition comprising a projectile; the projectile having a body comprising at substantially cylindrical body comprising a plurality of splines or knurl lines producing a corresponding plurality of grooves which extend along the length of a section of the main diameter of the main body; a deformable jacket means substantially surrounding a proportion of the diameter of the main body corresponding to the section of said main body comprising said splines or knurl lines; wherein the body of the projectile is formed from a metal having a Vickers Hardness of not less than 550 HV, and the maximum diameter of said main body comprising said splines or knurl lines being substantially equal to or less than the minimum internal diameter of the weapon barrel.  
   
   
       2 . A combination according to  claim 1  wherein the projectile has an ogival nose portion of the body forward of said forward body portion.  
   
   
       3 . A combination according to  claim 1  wherein the depth of said grooves is between about 1% and 10% of the nominal diameter of the projectile.  
   
   
       4 . A combination according to  claim 3  wherein the depth of said grooves is between about 2% and 6% of the nominal diameter of the projectile.  
   
   
       5 . A combination according to  claim 1  wherein the projectile body is made of a material selected from the group comprising steel, tungsten, alloys of tungsten, and tungsten carbide.  
   
   
       6 . A combination of gun and ammunition according to  claim 1  wherein the diameter of the main body is less than or equal to the diameter defined by the roots of the said rifling grooves.  
   
   
       7 . A combination of gun and ammunition according to  claim 6  wherein the diameter of the main body is substantially the same as the diameter defined by the roots of the said rifling grooves.  
   
   
       8 . A combination of gun and ammunition according to  claim 1  wherein the diameter of the body portion is less than or equal to the diameter defined by the said lands.  
   
   
       9 . A projectile for use in a combination as claimed in  claim 1;  the projectile having a main body comprising a substantially cylindrical body portion, and a plurality of longitudinally extending knurl lines or splines resulting in corresponding grooves along said main body; wherein the body of the projectile is formed from a metal having a Vickers Hardness of not less than 550, and the maximum diameter of said main body comprising said splines or knurl lines being substantially equal to or less than the minimum internal diameter of the weapon barrel.  
   
   
       10 . A projectile according to  claim 9  wherein the depth of the said annular groove is between about 1% and 10% of the nominal diameter of the projectile.  
   
   
       11 . A projectile according to  claim 1  wherein the projectile body is made of a material selected from the group comprising steel, tungsten, alloys of tungsten, and tungsten carbide.  
   
   
       12 . A projectile according to  claim 1  having nominal calibre of 9 mm or less.  
   
   
       13 . A projectile according to  claim 12  wherein the said nominal calibre is 5.56 mm.  
   
   
       14  and  15 . (Canceled)