Luth-AR H1 Carbine Buffer, Fits AR-15 Rifles BS-11T Luth-AR's .223/5.56 H1 Carbine Recoil Buffer assembly contains 1 tungsten slug and 2 steel slugs in the buffer for a total weight of 4 oz. Using a heavier AR-15 buffer helps improve reliable function with mid-length or shorter gas systems. You may also experience a reduction in felt recoil.