Lower Parts Kits Pistol Buffer Tube Assembly w/ T-3 Buffer$91.75.308 Buffer Tube Assembly$84.95.308 Billet Small Parts Kit$39.00Pistol Buffer Tube Assembly$89.95Mil-Spec 6-Position Buffer Tube Assembly$84.95 – $91.75Standard Lower Parts Kit$45.00 – $79.95Enhanced Lower Parts Kit$114.00 – $172.95Magpul CTR Mil-Spec Complete Kit$148.95.308 Standard Parts Kit$72.00Spike’s Complete M4 Stock Kit$124.95