The early Russian SKS's have a spring opposing the firing spring, This feature just simply disapered in later models. There are companys that will turn down your firing pin and install a spring. this is great if you use commercial ammo. But not really required. If you firing pin does not rattle in the bolt, you might have a problem. It should move under it's own mass. ( gravity). In the worl of unmodifed SKS'S .. Remove all the Cosmo,(difficult but possible) Use hard primer Ammo. And get to know your weapon. Shoot it a lot. And record the results. Kepp track of what works good in you gun. No two are the same.
