Combine this CMMG AR-15 Complete A1 Style Receiver Extension/Stock Kit with your choice of lower parts kit to complete your lower group.Features:Kit includes receiver extension tube, end cap, recoil spring and buffer, stock and stock screw
Aim Sports Upper Receiver Vise Block for AR-15 Style Rifle - ATUVB Original price was: $17.99.$15.99Current price is: $15.99. 
Strike Industries T-Bone Charging Handle for AR-15/M4/M16 Upper Receivers - SI-AR-TBCH-223-BK-RED Original price was: $41.99.$36.99Current price is: $36.99. CMMG Rifle Length Receiver Extension Stock Kit For AR Rifles, Black – 55CA646
Original price was: $105.99.$94.99Current price is: $94.99.