Aero Precision APVG100038A VG6 Gamma 5.56x45mm NATO SL 1/2-28 tpi 17-4 Stainless Steel Black Nitride for AR-15″

The Gamma 556SL is long enough to provide an overall length of 16 when permanently affixed to the barrel. Its outside diameter of .745 inches allows you to install and service your gas system without removing the muzzle brake. The 3-chamber design looks great on any standard profile barrel while effectively eliminating recoil leaving your rifle shooting flat and soft. Made in the USA.”