Bayonets
When the Soviet Union switched to the AK-47 as its field issue weapon in 1956, the country had a surplus of SKS 45s, which it shared liberally with other Soviet-bloc nations and allies. Among the first recipients were the Chinese who quickly began modifying the weapon, beginning with the bayonet attached to the end of the muzzle. The Soviet bayonets were blade styled. Although the Chinese manufactured much of the rest of the early carbines nearly identical to the Russian style, they retrofitted the SKSs with retractable spiked blades. Both the Russian and Chinese blades were retractable and both made shorter blades for issue to paratroopers, though the spike bayonet of the Chinese SKS was shorter than the bladed Russian paratrooper model. Also, Chinese paratrooper rifles had the sling swivels on the side of the rifle, not the bottom, which was the Soviet's design.
Stamped vs. Milled Bolt Carriers
Although the armory itself remained essentially the same, after the Chinese made the first SKSs marked up to 9 million, they stopped milling the bolt carriers. All bolt carriers on Chinese SKS rifles marked with numbers higher than 9 million were stamped instead of milled. Not only was it cheaper for an already inexpensively produced weapon, the stamping process was even and bending process was cheaper still. The bolt carrier is located at the opposite end of the muzzle, which holds the firing pin immediately adjacent to the bullet chamber that fires the bullets. Russian bolt carriers were milled from blocks of steel and believed to be stronger, more rigid, more reliable and, as a result of the extra work in milling, more expensive.
Muzzle Brake
The muzzle brake is attached to the end of the muzzle with holes in it to allow the powder vapor from bullets to escape more readily, reducing the recoil by as much as 50 percent. All the Russian built SKS 45s were fitted with muzzle brakes that were perpendicular to the rifle barrel, blunt, slightly rounded with holes in them that allowed the gasses from the fired bullets to escape more easily. The initial Chinese muzzle brakes employed the same design but were later re-designed with a slight top-to-bottom vertical slant, believing it reduced the sound of the bullets that were fired. While the muzzle brake did, in fact, reduce the recoil experienced by the soldier firing the weapon the muzzle brake also made discharge of the weapon much louder.
Manufacturer's Markings
Lest their be no mistake in which country the SKS 45 was manufactured, the marking on the weapons barrel leaves no room for discrepancy. The top cover of the rifle is the first place to look for the factory in which it was made, its serial number and the year it was produced. There were only two factories in Russia that produced the SKS 45s and each had its own distinguishing mark. Both were state-owned. The largest production of the SKS 45s came from the Tula factory. That plant began producing the SKS 45s from the weapon's inception in 1949 to early 1956. Its products are branded with a star that has a forward (upward) insignia. The other factory, the Ichevsk Armory, produced the SKS 45s in 1953 and 1954. They marked their carbines with a circle around a triangle and forward (upward) pointing arrow.