This AR-10 Complete Upper has a 18" 416R Stainless heavy barrel, and features a 1:8 Twist Rate, a Rifle length gas system. It includes a 15" MLOK Split Rail, an M4 flat-top billet upper receiver with forwarding assist, a Bolt Carrier Group, a Flash Hider, and a rear Charging Handle. It is chambered in 6.5 Creedmoor. This has the new handguard. This 6.5 Creedmoor upper is compatible with 1st gen DPMS low profile lowers.