CAR15/M4 5.56/9mm Xtra Power Buffer Spring $24.97 CAR-15, M4, & 9mm SMG action spring extra power. 16501 Out of stock Categories: AR-15, Wolff Gun Springs Related products 45 Degree folding backup sights $95.00 High Standard Bolt Carrier Group 5.56, new, made in USA. $499.00