SKS - Design

Design

The SKS has a conventional carbine layout, with a wooden stock and no pistol grip. The SKS is a gas-operated weapon that has a spring-loaded operating rod 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 higher muzzle velocity.

Contrary to popular belief, the SKS is not an assault rifle, because the basic design lacks both a selective fire capability and a detachable magazine. The SKS's ten-round box magazine is fed from a stripper clip and rounds stored in the magazine can be removed by depressing a magazine catch located forward of the trigger guard (thus opening the "floor" of the magazine and allowing the rounds to fall out). In typical military use the stripper clips are disposable. If necessary they can be reloaded multiple times and reused.

While early Soviet models had spring-loaded firing pins, most variants of the SKS have a free floating firing pin within the bolt. Because of this design, care must be taken during cleaning (especially after long storage) to ensure that the firing pin does not stick in the forward position within the bolt. SKS firing pins that are stuck in the forward position have been known to cause accidental "slamfires" (uncontrolled automatic fire that empties the magazine, starting when the bolt is released). This behavior is less likely with the hard primer military-spec ammo for which the SKS was designed, but as with any rifle users should properly maintain their firearms. For collectors, slamfires are more likely when the bolt still has remnants of cosmoline embedded in it. The firing pin is triangular in cross section, and slamfires can also result if the firing pin is inserted upside down.

In most variants (pre-1970 Yugoslav models being the most notable exception), the barrel is chrome-lined for increased wear and heat tolerance from sustained fire and to resist corrosion from chlorate-primed corrosive ammunition, as well as to facilitate cleaning. Chrome bore lining is common in military rifles. Although it can diminish actual accuracy, this is not a real limit on practical accuracy in a weapon of this type.

The front sight has a hooded post. "The rear sight is an open notch type which is adjustable for elevation from 100 meters to 1000 meters (110–1100 yards). There is also an all purpose "battle" setting on the sight ladder (marked "П"), set for 300 meters (330 yards). This is attained by moving the elevation slide to the rear of the ladder as far as it will go.". "The Yugoslav M59/66 has folddown luminous sights for use when firing under poor light conditions."

All military SKSs have a bayonet attached to the underside of the barrel, which is extended and retracted via a spring-loaded hinge. Both blade and spike bayonets were produced.. Some versions, such as the Yugoslavian-made M59/66 variant, are also equipped with a grenade launching attachment..

The SKS is easily field stripped and reassembled with only a punch. The rifle has a cleaning kit stored in a trapdoor in the buttstock, with a cleaning rod running under the barrel, in the same style as the AK-47. In common with some other Soviet-era designs, it trades some accuracy for ruggedness, reliability, ease of maintenance, ease of use, and low manufacturing cost.