“Rock River Arms AR2120 LAR-15 A4 223 Rem/5.56 NATO 10.5″” 30+1 Hogue Grip Blk RRA LAR-15 A4 is offered in 2 barrel lengths. Both made of chrome moly, the 7″” has a 1:9″” twist, while the 10.5″” has a 1:7″” twist. The upper receivers on these pistols are forged and the lower receivers are chambered in .223/5.56. They have a gas block sight base and come with an A2 flash hider. The 7″” model features a black aluminum free-float tube handguard and the 10.5″” has a black R-4 handguard. Hogue rubber grips round out the weapon.”