Bent pushrod could be the prob with shell casing eject. Had to replace the one in my Romanian. Pull it and roll it on table to check straightness. Clean the smaller end piston too and look for spurs or burrs. Also poke out the port to barrel with toothpic while yer at it. The Yugo SKS has an adjustable port that can be entirely closed for using the grenade launcher. Fiddling with it will mess it up though, makin it come loose. And does your Chinese SKS also stovepipe rounds?
Noticed with mausers ammo primer cap recesses vary. Turk for example generally wouldnt fire with my Portuguese 1904/39. What kinda ammo ye feedin the SKS? Chinese Tiger ammo could have further recessed primer than the rest. Meanwhile Wolf is notorious for shellacked casings stickin at chambers.
All milsurp ammo burns dirty. I used to soak the SKS sliding block in Hoppe's after each afternoon's shooting. Sticky firing pins cause slam fire. There's millions of accessories available for SKS, probly more than for any other mil-surp rifle. Firing pins aint interchangable among nations of origin. Look for wolf spring kits to improve action. Also
www.kivaari.com for trigger work - Texas gunsmith who specializes in SKS.
Where did the stock crack?? Lemme guess right behind the receiver, common problem. There's ultra-light dragonov fiberglass stocks available, Choat makes the best of em.
SKS are hilarious little commie-guns with their folding bayonet that doubles as monopod. 7.62x39 drops like a stone beyond 100 yrds though. And thin walled chrome bores are notorious innacurate when they git heated up. The holy grail among SKS collectors is probly the East German version, also North Korean - snatch it if ye see one.
I believe Norinco also made a Makarov pistol. And the Norinco replica WWI trench gun / shotgun is one of the coolest weapons you'll ever see. Heat shield covers the barrel, has bayonet lug and sling. Can be fired fast as you can pump it, holding the trigger back it fires immediately on chambering each round. Also barrell length is short and the tube holds 8 rnds if memory serves me well. Hellacious little pump gun thats more fun than barrel of monkeys.
(:=