Description If you experience feeding problems with your upper, 99% of the time, the issue is due to the customer using a sub-standard bolt from an alternate manufacturer. The construction of the bolt, extractor, and ejector are all extremely important for proper feeding of the 450 Bushmaster cartridge. Barrels are available in 12.5″, 16.25″, and 18″ dimpled for gas block screw alignment. An adjustable gas block is recommended for Suppressed use. Light-Weight barrel profile is 790″ under the hand guards, .750″ at the gas block, and .730″ at the muzzle. 12.5″ Barrels have a carbine length gas system, 5/8-24 muzzle thread, 4150 steel, 1:20 twist. 1.20 pounds. Requires adjustable gas block for Super Sonic and Suppressed use. 16″ Barrels have a carbine length gas system, 5/8-24 muzzle thread, 4150 steel, 1:24 twist. 1.52 pounds. 18″ Barrels have a mid-length gas system, 5/8-24 muzzle thread, 4150 steel, 1:24 twist. 1.70 pounds SB 704 applies to all California sales – Must ship to FFL.
