This Brownells’ exclusive AR-15 Upper Receiver is Made in the USA. Chambered in 300 Blackout and featuring a 16” barrel with a 1:8 twist. The standard A3 13-slot aluminum flat top receiver comes with a 10” handguard utilizing the KeyMod rail system. A low profile gas block, forward assist, ejection port cover and phosphate finish help to complete this package. Left out of this upper are the bolt carrier group as well as the charging handle so you can customize the upper any way you want! The A3 upper receiver will attach to almost any standard AR-15 lower receiver.