Gun barrel rifling

Abstract

The present invention relates to polygonal rifling of a gun barrel to provide grooves and bores in the gun barrel separated by a flat area which tapers from the bore to the groove. There is an angle from the center of the bore to the corner of the flat area, that is, where the flat area meets the bore. The angle is predetermined by the bore dimensions.

1 . A gun barrel having polygonal rifling comprising helically disposed rifling grooves in a barrel bore and having a flat area between said grooves and said bore, said flat area including corner areas, wherein the groove diameter is greater than the bore diameter and the flat area dimensions which connects the groove diameter and the bore diameter is less than the bore diameter. 
     
     
         2 . A gun barrel according to  claim 1  wherein there are six grooves and six bores. 
     
     
         3 . A gun barrel according to  claim 2  wherein the groove diameter is about 0.224 inches, the bore diameter is about 0.219 inches and the flat diameter is about 0.215 inches. 
     
     
         4 . A gun barrel according to  claim 3  wherein an angle from the center of the bore area to the corner of the flat area is about 4.7 degrees. 
     
     
         5 . A gun barrel according to  claim 1  wherein the rifling provides a twist in the rifled barrel which is substantially uniform from the breech end of the barrel to the muzzle end of the barrel. 
     
     
         6 . A gun barrel according to  claim 1  wherein a bullet fired through the barrel will not have any substantial deformation due to the corners of the flat area between the bore and groove. 
     
     
         7 . A gun barrel according to  claim 1  wherein a bullet fired through the barrel follows the helix angle of the rifling and the stress from the wind up effect of the bullet of the corners of the polygonal shape creates substantially no or little bullet deformation.