The Angstadt Arms 1045 matched receiver set is the foundation for a quality pistol caliber AR-15. Machined from a solid block of 7075-T6 billet aluminum"" the 1045 receiver is compatible with 45ACP and 10mm GLOCK magazines. Featuring standard AR-15 controls and accepting most aftermarket components"" the 1045 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 slick side upper receiver features an appropriately sized ejection port and no forward assist. The receiver set can be completed with standard mil-spec components.