whatever your gun likes. without measurements like speed and dimensions and other factors all you can do is find the ammo your gun likes and then buy a bunch of it.

Now that said I have found the silver bear a little slower than surplus and wolf slower still. Also understand that wolf uses .308 bullets. I have not checked to see if I have a box of silver bear left to check. My reloads all use .310 bullets.

The SKS using a tilting bolt design can be very ammo sensitive to the powder charge and each one is different. Also, what kind of scope mount are you using? the top cover mounts are just about useless unless you lock it down using set screws and even then they can wander.

Just some thoughts.