First off, the SKS does not chamber a full power cartridge. It shoots the Russian intermediate cartridge, namely 7.62x39 (7.62x25 is less powerful and 7.62x54 is more powerful). It was sort of Russia's first attempt at an assault rifle.
The Mosin-Nagant is chambered for the far more powerful 7.62x54 Rimmed cartridge. In a short barreled version (carbine), like my M44 or the M91/39 (think that's the number), the recoil is brutal. A stock replacement could probably tame the beast. I have no experience with the full-length rifle. My Polish made M44 is surprisingly accurate. As it is now, I believe I can outshoot any of my other military surplus rifles (Garand, FAL, Enfield). Keep in mind that extending and locking the bayonet, instead of leaving it folded (M44 only), will change the point of impact somewhat. My Polish M44 has about the best fit and finish of any other M44 I've seen. You'll love it for the $130 price!