The Soviet Arms 5.56 Krink complete Bolt and Carrier are made of Hammer Forged Steel and feature a Black Oxide Coating. The Soviet Arms 5.56 Krink 4340AQ Hammer Forged Front Trunnion has the 5.56x45mm Bullet guide installed. Designed to function on Soviet Arms Krinks. Due to the wide variety of AK manufacturers fitting may be required.