Complete M5/308 AR-10 Lower- Assembled Aero Precision M5/308 Lower receiver with A2 grip, buffer tube and spring. Add a barreled upper and collapsible stock to finish your build. Buffer tube fits is Milspec dimension (7.25" long and 1.15" dia) collapsible stocks. Receiver is serial numbered and marked "Multi" caliber. Delivers to your local FFL.- Compatibility: This receiver fits all Aero Precision and DPMS compatible barrels, BCGs, parts, and Upper Receivers.