Saiga 12K Shotgun is the best known member of Saiga shotgun series. Other versions include 20 gauge and .410 gauge shotguns.
Developed at IZJMASH (ИЖМАШ) in the beginning on 1990, Saiga technically copies the construction of AK-47 assault rifle, scaled up to accept shotgun ammunition. Both AK-74 and Saiga parts are fully interchangeable, since the Saiga is designed and built with parts used for assault rifles; the only visible difference is the barrel for shotguns.
Saiga is restricted to semi-automatic action only, and uses single-stack detachable magazines for five (5) or eight (8) shells. It accepts both standard 12 gauge ammo (2 3/4 inches long) and magnum 12 gauge ammo (3 inches long) interchangeably. Construction includes gas vent, that is used to select the type of used ammo.
Plastic stock is folding to the left. Civilian versions of Saiga have a safety mechanism, which prevents firing with folded stock, to comply with Russian law restricting the minimum length of civilian firearms. (Some of the export models do not have this restriction, however.) Grips are plastic as well. Other parts are stamped steel.
Saiga has the standard Russian optics mount, common to all of the AK series. Additionally, the barrel is threaded for a screw-on choke.
In some countries with laxer gun laws, Saiga can also be outfitted with an extended mag (10 shells), but in Russia, such magazines are illegal (8 cartridges in magazine restriction).
The Saiga shotguns and rifles that are imported to the US have been "sporterised". They do not have a pistol grip, or folding stock, they come with a stock that has the grip as well. This requires the fire control group to be moved back, and the trigger comes out through the hole that the pistol grip would normally attach.
The gun can be illegally modified to fire in fully-automatic mode, but apparently, due to relatively small weight of the gun, control during automatic fire is minimal, and, coupled with limited magazine capacity (unless 20 or 30 round drum magazines are used), does not afford any advantage over semi-automatic mode.