what is polygonal rifling
Conventional eight groove rifling on the left, and octagonal rifling on the right. Polygonal rifling /pÉËlÉªÉ¡ÉnÉl/ is a type of gun barrel rifling where the traditional lands and grooves are replaced by hills and valleys in a rounded polygonal pattern, usually taking the form of a hexagon or octagon.n the Glock pistol, for instance, octagonal rifling is used in the large diameter .45 ACP bore, which has an 11.23 mm (0.442 in) diameter, since it resembles a circle more closely than the hexagonal rifling used in smaller diameter bores.