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 Colt AR-15/M-16/M4, Reduced Power Trigger Function Pak $19.97 AR15/M-16 5.56/.223 Std Power Buffer Spring $24.97