The Popular SKS
Originally a Soviet semi-automatic carbine designed in 1945, the Самозарядный карабин системы Симонова (we’ll just call it the SKS from here on out) was widely used by Eastern Bloc nations, but has since been replaced, for the most part.
The rifle we’re shooting here was Yugoslavian surplus, packed in cosmoline (disgusting stuff, by the way), and boxed away for decades. It retains its original bayonet and 10-round fixed magazine (which is fed using the pictured stripper-clips).
Some SKS rifles sport spring-loaded firing pins, but this one is equipped with a free-floating pin that must be handled with care. Should it get stuck in the forward position—and yes, this does happen with all of that cosmoline packed in there—a slamfire could be triggered, emptying the entire magazine as soon as the bolt is released.