14.5" Lightweight 5.56mm Stainless Barrel --1 in 7" twist improved polygonal rifling --Extended feed ramps --Bead blasted finish --Mid length gas system --Gas tube --Pinned Low Profile Gas Block --1/2x28 threads --Light Contour Weight: 29oz The barrel ships with gas block installed. This barrel is designed for our gas block that is 1" long(INCLUDED). A standard front sight base is 1.9" long and WILL NOT FIT. Barrel installation should be performed by a qualified gunsmith. Installation of the gas block dowel pin and gas block is required to complete the assembly process.