Dad brought his Yugo 59/66 SKS over last weekend so I could get a good look at it,and see if I could find out why it's shooting all over the place and won't keep zero on the scope. I suspected it was the cheesy $40 scope and/or the receiver cover mount that the shop sold him when he bought it,and I confirmed it with some open sighted shooting this afternoon.
I ran 80 rounds through it-20 rounds checking out the open sights for range adjustment, and the other 60 rounds were on a separate target as fast as I could acquire a sight picture and reload the gun.
Just a heads-up....an SKS gets HOT after 40 rounds fired at a fairly quick pace...hot enough that I had some cosmoline residue bubbling out of the wood handguard

. The last 20 rounds were difficult to hold the gun steady-it was really hot. I'll say this though,the thing is a blast to shoot-lotsa fun with minimal recoil or noise. I can definitely see myself buying one of these later on. All 80 rounds were shot from 75 yards from a bench with a makeshift rest. It put 51 rounds of the 60 in the 9 ring (8" circle),and only two right at the bottom edge of the 8 ring with the rest all just above the 9 ring. IMO-the gun's shooting fine-esp for a combat designed semi-auto manufactured in the 50's. I'll take a moderately priced spare 4X scope I've got here back out later and see if it's the el-cheapo scope or the mount itself that's not keeping zero.
Anyway-the thread would be worthless without pics...so here's one of the target...

"The Constitution of most of our states (and of the United States) assert that all power is inherent in the people; that they may exercise it by themselves; that it is their right and duty to be at all times armed."
-Thomas Jefferson.
6/14/08-CHL Class
10/15/08-Plastic in Hand