The SKS has a conventional layout, with a wooden stock and rifle grip. The SKS is a gas-operated rifle that has a spring-loaded bolt carrier and a gas piston rod that work the action via gas pressure pushing against them. Also, it has a "tilting bolt" action locking system. The SKS is shorter and less powerful than the semi-automatic rifles that preceded it, such as the Soviet SVT-40. However, the SKS has a 4-inch longer barrel than AK-series rifles, which replaced it; as a result, it has a slightly higher muzzle velocity.