The Angstadt Arms 0940 lower receiver set is the foundation of a quality pistol caliber AR-15. Machined from a solid block of 7075-T6 billet aluminum, the 0940 lower receiver is compatible with 9mm, .40 S&W and 357 Sig GLOCK magazines. Featuring standard AR-15 controls and accepting most aftermarket Mil-Spec components, the 0940 is instantly familiar to anyone experienced with the AR-15/M4 platform. To aid in reloads, the receiver features a flared magazine well and last round bolt hold open design which locks the bolt open on an empty magazine. The lower receiver can be completed with standard mil-spec components.