The SKS is a rifle that was designed to be used by Russian and Chinese plowboys with a minimum amount of care and maintenance. It was also designed to hit a man (American male by the way, we are larger than the others) sized target at 300 meters. No one ever said where the round had to hit. I agree with E. BeauBeuax, about 6 inches is good, 8 inches is more like normal for these rifles.
I have two of these puppies. One will do a two inch group at 100 yards from a rest using hand loaded ammo. With surplus this becomes four inches. The other, a ratty old Chi-Com early surplus, averages in at about 6 no matter what it is fed.
As an interesting note on the old Chi-Com version. I decided one day that it was time for this thing to die. I was looking for an excuse to buy the other and had to come up with something to tell the Mrs. So off to the range with 1500 rounds of surplus ammo. I sat there and loaded and fired this thing until the entire brick of 1500 was gone. The only break I took was to go visit the men's room and to reload. The barrel was so hot that it sizzled water when a drop fell on it. Guess what, no mis feeds, no jams, no nothing. The blasted thing is sitting in the gun safe and it still works. It may not be pretty, it may not put the round exactly where you want it, but it never stopped firing. A true testimony to simple design.
Joe