Bushmaster BFSIII 5.56 NATO Built Lower Receiver with M4 Stock

Primary Weapons Systems MK1 Mod 2-M Complete Lower 5.56 30-Rounds

FMK Firearms AR-1 Blue 5.56 NATO / .223 Rem Stripped Lower

American Defense UIC Stripped Lower 5.56/.223

Spikes Tactical Enhanced Lower Parts Kit Black .223 Rem / 5.56 with ST Battle Trigger

Rise Armament Stripped Lower Receiver Black 5.56

Radian Weapons A-DAC 15 Complete Lower 5.56 / .223 Rem w/ SBA3 Brace

LWRC IC Complete Lower Black 5.56 / .223 Rem