I've had poor accuracy with Bear and Golden Tiger in all my SKS's and AK's. I usually look for surplus yugo that has been stored well. The yugo's use a hotter load. Had good luck with cz, russian, and romanian.
Have heard from numerous folks that polish ammo is good but haven't used it myself.

Yes, for sure check your scope. Very few sks scope mounts are worth a shit. I use a b-square cover mount, but I put a hex fastener through the front of the cover and into the receiver. After cleaning and reassembly it's always right back on zero.