Best Seller | Wilson Combat Ar-15 Super-Stoc Retro-Fit Buttstock Kit For your next custom AR-15, M16, M4 build. The Wilson Combat Carbine receiver extension machined from 7075-T6 aluminum and manufactured to Mil-Spec dimensions and specifications. Hard Coat Anodized per Mil-A-8625F, Type III, Class 2. These tubes... ... more Wilson Combat Ar-15 Super-Stoc Retro-Fit Buttstock Kit For your next custom AR-15, M16, M4 build. The Wilson Combat Carbine receiver extension machined from 7075-T6 aluminum and manufactured to Mil-Spec dimensions and specifications. Hard Coat Anodized per Mil-A-8625F, Type III, Class 2. These tubes... | | $51.95 go to store |