The EPC-9 lineup is perfect for your next 9mm or 40S&W AR build. Built from the ground up to meet the extreme demands of pistol caliber blowback ARs, the EPC-9 is precision machined to the same high standards you have come to expect from Aero Precision. The foundation of this product line is our forged EPC-9 receiver set, accepting standard frame GLOCK magazines and available with a last round bolt hold open mechanism integrated into the upper receiver.