IWI US, Inc Centerfire, K, Suppressor, 6MM, 1/2X28 HUN-T Mount, Black IWS6K The IWI IWS6K silencer is a 6mm diameter, reduced back-pressure solution designed for 5.56 NATO and 6mm rifles. Constructed with weapon-grade nickel alloy and stainless steel parts, and CNC laser-welded for durability, it withstands the demands of short barrels and full-auto firearms while preserving the rifle's inherent accuracy.