Rifled ammunition system

Abstract

Gun and ammunition solutions which permit the use of High Explosive (HE) rounds and Armor Piercing Fin Stabilized Discarding Sabot (APFSDS) rounds in one weapon. A first system has a gun barrel chamber sized to receive the outer cases of both APFSDS and HE rounds. The chamber has a smooth rear section which abuts a front section having internal helical rifling. A HE round has an outer case with a length that is the same as the length of the smooth rear section of the barrel. A projectile held by the case has a rotating band on a rear end configured to engage the internal helical rifling in the chamber. A second system has a conventional smooth barrel and utilizes a HE round with an outer case having internal rifling in a forward section. A projectile held by the outer case has a circular band mounted to rotate about a rear end thereof to engage the internal rifling.

What is claimed is: 
     
         1 . A gun barrel for use with both armor-piercing and high explosive rounds, comprising:
 a chamber adjacent a breach and having a diameter sized to receive the outer cases of both armor-piercing and high explosive rounds, the chamber having a smooth rear section which abuts a front section having internal helical rifling.   
     
     
         2 . The gun barrel of  claim 1 , wherein the front section has a length of about half of the chamber length. 
     
     
         3 . The gun barrel of  claim 2 , wherein the chamber length is between 8-15 inches. 
     
     
         4 . The gun barrel of  claim 3 , wherein the chamber length is 12 or 13 inches. 
     
     
         5 . The gun barrel of  claim 1 , wherein the front section is straight and the rear section is tapered. 
     
     
         6 . A high explosive round for use with the gun barrel of  claim 1 , wherein the high explosive round has an outer case with a length that is approximately the same as a length of the smooth rear section of the chamber of the barrel. 
     
     
         7 . The high explosive round of  claim 6 , further including a projectile held by the case with a rotating band on a rear end thereof configured to engage the internal helical rifling in the front section of the chamber. 
     
     
         8 . An armor-piercing round for use with the gun barrel of  claim 1 , wherein the armor-piercing round has an outer case with a length that is approximately the same as the chamber length and a sealing ring at a forward end sized to engage a smooth bore portion of the barrel forward of the chamber. 
     
     
         9 . The gun barrel of  claim 1 , wherein the internal helical rifling has a helix angle of between 20-26°. 
     
     
         10 . A high explosive round for use in a smooth bore gun barrel, comprising:
 an outer case containing a propellant charge in an inner cavity terminating in a rearward closed end and having internal helical rifling in a forward section, the outer case having a longitudinal length along an axis and wherein the internal helical rifling is disposed only in the forward section;   a projectile held by the outer case in a forward position of the cavity, the projectile having a circular band mounted to rotate about a rear end of the projectile, the band positioned at a rear end of the forward section with internal helical rifling.   
     
     
         11 . The high explosive round of  claim 10 , wherein the band also has external helical rifling at the same angle as an angle of the internal helical rifling. 
     
     
         12 . The high explosive round of  claim 10 , wherein the band is formed of plastic. 
     
     
         13 . The high explosive round of  claim 10 , wherein the band is formed of metal. 
     
     
         14 . The high explosive round of  claim 10 , wherein the longitudinal length of the outer case is between about 8-15 inches. 
     
     
         15 . The high explosive round of  claim 14 , wherein the longitudinal length of the forward section is about half the longitudinal length of the outer case. 
     
     
         16 . The high explosive round of  claim 15 , wherein the band has a length of between 5-10% of the longitudinal length of the outer case. 
     
     
         17 . The high explosive round of  claim 14 , wherein the band has a length of between 5-10% of the longitudinal length of the outer case. 
     
     
         18 . The high explosive round of  claim 10 , wherein the band has a length of between 5-10% of the longitudinal length of the outer case. 
     
     
         19 . The high explosive round of  claim 10 , wherein the internal helical rifling in the forward section has a helix angle of 20-26°. 
     
     
         20 . A firearms system comprising the high explosive round of  claim 10 , and further including:
 a gun having a smooth bore barrel with a chamber having a length the same as the longitudinal length of the outer case of the high explosive round; and   an armor-piercing round having an outer case with a length the same as the longitudinal length of the outer case of the high explosive round and a sealing ring at a forward end sized to engage the barrel forward of the chamber.