I had the same problem, the gun wasn't grabbing new links. I bought it used from a local dealer, and the cam on the bottom was tightened all the way down, so I loosened it up a quater turn. It cycled much better after that, but it still didn't feed very well. Turns out one of the springs in the top cover had cracked, so I replaced that, and I think it's all better now, but I haven't had a chance to shoot it yet.
It's an Izzy .308, and I had some belts, but I'm going to try links for it now and see if that improves function.