Patent ID: 6679178
Filing Date: 2004-01-20
Classification: F42B

Abstract:
A projectile round (40) in combination with a gun barrel and a breech block comprising, the gun barrel having a smooth tubular central bore (20) defining a muzzle end (20B) and a breech end (20A), said breech end including a breech block (50) and said breech block containing a front surface with ridged flukes disposed on said front surface (50A), said projectile round comprising a cartridge case (30), said cartridge case comprising an open front surface (30A) and a closed rear surface with ridged flukes disposed on the outside of said closed rear surface (30D), and a forward portion of a smaller diameter which tapers to a rearward portion (30B) of a larger diameter, said ridged flukes of said closed rear surface of said cartridge case are adapted to congruently fit said ridged flukes of said breech block when said projectile round is loaded in said breech end of said gun barrel, said rearward portion containing a propellant chamber (30C) and said forward portion containing a rifled inside surface (30A) defining corresponding lands (32) and grooves (34), said projectile round further comprising a projectile (40) disposed in said cartridge case, said projectile having ogival shaped front (40A) and rear (40D) portions with short cylindrical portion (40B) connected adjacent to said ogival shaped front portion and a long cylindrical portion (40C) disposed adjacent to said short cylindrical portion, said short cylindrical portion and long cylindrical portion having substantially the same diameter as an inner diameter of said forward portion of said cartridge case, said long cylindrical portion comprising a rifled outer surface with corresponding lands (42) and grooves (44) disposed along the length of said long cylindrical portion to engage the lands and grooves of said rifled inner surface of said forward portion of said cartridge case in a congruent fit when said projectile is mounted into said cartridge case with said rear portion of said projectile disposed inside said propellant chamber of said rearward portion of said cartridge case and said short cylindrical portion adjacent the said front ogival portion of said projectile extending outside of said front portion of said cartridge case and into said gun barrel when said projectile round is loaded into said gun barrel with the outside diameter of the short cylindrical portion adjacent the front of said projectile being slightly smaller than the inner diameter of said gun barrel to provide a sliding fit, whereby upon igniting a propellant (60) in said propellant chamber of said cartridge case, a rotational motion is imparted along the lands and grooves of said projectile in response to the propellant charge as said projectile travels along the lands and grooves of said inner portion of said forward portion of said cartridge case and exits said forward portion of said cartridge case and enters the gun barrel with said cartridge case being secured by said congruent fit of said ridged flukes on said breech block and said rearward portion of said cartridge case, against rotational motion.