Windham Weaponry Gov't AR15 Rifle R20GVTA4S. This semi automatic AR15 rifle is chambered in .223/5.56NATO and features a 20" Gov't profile barrel with a 1:9" twist. This classic AR-15 features a milspec trigger, A2 grip and front sight, Rifle length handguard, carry handle and an aluminum receiver. If you want that old school classic AR15 look with a modern build and features than this rifle is for you. Backed by Windham Weaponry's lifetime warranty this rifle is built to last.