Aero Precision APAR501603 AR-15 Multi-Caliber Brl Finish The AR-15 stripped upper receiver is one of Aero's most popular products. Forged from 7075-T6, this stripped upper is precision machined to mil-spec M16/M4 specifications and features M4 feedramps. Match this upper with one of the Aero AR-15 lower receivers for a solid and dependable fit. Features M4 feedramps, .250 takedown pin holes, lazer engraved T-Marks. AR-15 stripped upper receiver in Anodized black. Type: Stripped Caliber: Multi-Caliber Sights: None, Optic Ready Barrel Length: N/A Receiver Description: A3 Receiver Finish: Black Hard Coat Anodized