Chambered for .45 G.A.P. cartridge, which is slightly shorter than .45 ACP. Cartridge has a muzzle speed of 951 fps and muzzle energy of 405 ft. lbs. Fitted with 4.49" barrel; height 5.5"; overall length 7.3"; weight about 26 oz. Available with OD green frame. NOTE: Add $25 for all Gen4 variations.