The SKS is a Russian semi-automatic carbine, designed in 1945 by Sergei Gavrilovich Simonov. It is Self-loading Carbine, Simonov's system, 1945, or SKS 45. It was originally planned to serve as the new standard issue weapon for the Soviet military forces, alongside Mikhail Kalashnikov's new AK-47 design, to replace the Mosin-Nagant series of bolt-action rifles and carbines that had been in service since 1891.
As mass production of AK-pattern rifles increased, the SKS carbine was soon phased out of service. The carbine was quickly replaced entirely by the AK-47, but it remained in second-line service for decades afterwards, and remains a ceremonial arm today.
The SKS was widely exported and produced by the former Eastern Bloc nations, as well as China, where it was designated the "Type 56" (and, in modified form, the "Type 68"), East Germany as the "Karabiner S" and in North Korea as the "Type 63" It is today popular on the civilian surplus market in many countries.
The SKS carbine was chambered for the then-new 7.62 x 39 mm M1943 round, an intermediate cartridge which went on to be used in the Kalashnikov-series weapons.
The SKS has a conventional carbine layout, with a wooden stock and no pistol grip. Most versions are fitted with an integral folding bayonet which hinges down from the end of the barrel, and some versions, such as the Yugoslavian-made M59/66 variant are equipped with a grenade launching attachment.
As with the American M1 Carbine, the SKS is shorter and less powerful than the semi-automatic rifles which preceded it.
Contrary to popular belief the SKS is not a modern assault rifle. This is because it does not meet all of the criteria of a true assault rifle. It does not possess the capability for selective fire, and the basic design does not possess a removable magazine. Some selective-fire variants were produced in the PRC, however, the basic design of the SKS is semi-automatic in nature.
The sks carbine'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 (thus opening the "floor" of the magazine and allowing the rounds to fall out) located forward of the trigger guard.
Chinese SKSA standard SKS is semi-automatic and has a fixed/hinged 10 round magazine which is loaded from the top of the rifle manually either by inserting the ammunition one round at a time or with a disposable 10-round stripper clip. It is a gas-operated weapon that has a spring-loaded operating rod and a gas rod that work the action via gas pressure pushing against them. Also, it has a "tilting bolt" action locking system.
Some variants of the SKS have been modified, with limited success, to accept AK-47 detachable magazines (military rifles designed with fixed magazines often experience feed jams when modified to accept detachable magazines, and the SKS is no exception).
Norinco had at one point manufactured the SKS-M, SKS-D, and MC-5D models which were engineered from the factory to accept AKM magazines without problems (though the wood stock must be relieved to accept drum magazines). The SKS also has a slightly longer barrel than AK-series rifles, with a fractionally higher muzzle velocity.
While early Russian SKS models had spring-loaded firing pins, most variants of the SKS have a free floated 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 the user should properly maintain their firearm.
For SKS 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 it is inserted upside down. The firing pin should be dry, and rattle around loosely inside the bolt. The firing pins of most SKSs can be modified with a spring to resemble the early Russian models if the owner desires such.
In most SKS variants (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.
All military SKSs have a bayonet attached to the underside of the barrel, which is extended and retracted via a spring-loaded hinge (some are removable whereas some are permanent).
The SKS is easily field stripped and reassembled with no tools, except a screw driver is necessary to remove the stock. 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.
The SKS trades accuracy for ruggedness, ease of maintenance, ease of use, and low manufacturing cost. The SKS has a slightly longer barrel than AK-pattern rifles, with a fractionally higher muzzle velocity. In short, it is a simple design that is highly effective and rugged.
In 1949, the SKS was officially adopted into the Soviet Army, produced at the Tula Armory from 1949 until 1955 and the Izhevsk Armory in 1953 and 1954. Although the quality of Russian SKS's manufactured at these legendary state-run arsenals was quite high, its design was already obsolete compared to the Kalashnikov which was selective-fire, lighter, had three times the magazine capacity, and had the potential to be less labor intensive to manufacture. Gradually over the next few years, AK-47 production increased until the extant SKS carbines in service were relegated primarily to non-infantry and to second-line troops. They remained in service in this fashion even as late as the 1980s, and possibly the early 1990s.
The SKS was to be a gap-filling firearm produced using the proven operating mechanism design of the PTRS and using proven milled forging manufacturing techniques. This was to provide a fallback for the radically new and experimental design of the AK-47, in the event that the AK were to prove a failure. In fact, the original stamped receiver AK-47 had to be quickly redesigned to use a milled receiver which delayed production, and extended the SKS's service life.
Although the SKS was a front-line Soviet issued rifle for only two years, it has played a documented role in the two major Cold War conflicts - the Korean War and the Vietnam War - and several subsequent 'dirty wars'.
The SKS fell out of service amongst its client nations during the 1960s and 1970s, although the Chinese police and military forces continued to use it during the 1980s. Many surplus SKS rifles were disposed of in the 1990s, and photographs and stories exist of SKSs used by guerilla fighters in Bosnia, Somalia and throughout Africa and South-East Asia during the 1990s and 2000s.
During the Cold War, Russia shared the design and manufacturing details of the sks with its allies. Therefore, many variants of the SKS exist. Some variants use a 30-round AK-47 style magazine (Chinese Type 68 and 68/72, also known as "D" & "M" models), gas port controls, flip-up night sights, and prominent, muzzle-mounted grenade launchers (Yugoslav M59/66, possibly North Korean Type 63). In total, SKSs were manufactured by Russia, China, Yugoslavia, Albania, North Korea, Vietnam, and East Germany (Kar. S) with limited pilot production (Model 56) in Romania and Poland (Wz49.) Physically, all are very similar.
Early versions of the Russian SKS and later Chinese Type 56s (produced 1965-71) used a spike bayonet, whereas the majority use a vertically-aligned blade. Many smaller parts, most notably the sights and charging handles, were unique to different national production runs. A small quantity of SKS carbines manufactured in 1955-56 were produced in China with Russian parts, presumably as part of a technology sharing arrangement.
Many Yugoslav M59/66 series rifles were exported to Uruguay and Mozambique; the Mozambique versions having teakwood stocks, the wood supplied by that nation. The vast majority of Yugoslav M59 and M59/66s have elm, walnut and beech stocks. SKS carbines have also made appearances in recent conflicts in Africa, Afghanistan, and Iraq.
Nations that utilized the SKS but did not receive manufacturing rights included Afghanistan, Congo, Indonesia, Iraq, Laos, Lebanon, Mongolia, Morocco, the United Arab Republic (Egypt) and the Yemen People's Democratic Republic.
The SKS has also been featured prominently around the world during times of civil unrest. In the United States, the SKS was used successfully by Korean shopkeepers to fend off looters during the 1992 Los Angeles riots.
There is some debate as to the relative quality of each nation's SKS production; Yugoslav types are generally considered to be better made than Chinese, yet the Chinese types typically have chrome lined barrels while the Yugoslav versions do not.
Because of their historic and novel nature, SKS rifles are classified by the BATF as "Curio & Relic" items under US law, allowing them to be sold with features that might otherwise be restricted.