Aero Precision EPC-9, Stripped Lower Receiver, Semi-automatic, 9MM/40S&W, Anodized Finish, Black, Accepts Glock Style Magazines APAR620001AC The EPC-9 Lower Receiver delivers billet aesthetics in a forged package for your next pistol caliber build. This custom-designed enhanced forging is machined from 7075-T6 Aluminum and has several functional features, much like the M4E1, to help simplify the assembly process for the at home builder.