I also have a couple of turks that shoot in the 3-4 inch range without a problem, but they have horrible sights. These rifles I bought for around $50.

I picked up a Yugo m48 for $100 a couple of months ago also. The bore was really dark and crappy. The first time I shot it, it made something like 20" groups and I was really sad. when I got home, I plugged the barrel and filled it with copper solvent and allowed it to sit for a couple of hours. I then scrubbed the bore with a somewhat abrasive brass polish. The bore is still dark, but gets better the more I shoot it and clean it. It now will group around 4-5 inches, but I think it has potential to shoot better.