The gun has seen nothing but Challenger 1oz target loads. This is my second Nova, the first one I foolishly sold off one ever jammed once on me in the 5000 rounds or so I put through it, this one did it right out of the box. First, I thought it was a defect in the gun, the second time it did it, I realized both ends of the shell were marked which I then reliazed I must be short shucking it occasionally then it hits the end of the chamber pushing the action bars under the breach bolt which jams the action up solid. I then pulled the action pins, the bars drop back in place and the gun works like nothing happened. I took the burr off of it, re-assmebled the gun and ran a dozen or so shells through the action as fast as I could without a hiccup by holding the action release down. No marks on any of the shells. I'll give it a shot next monday after I have it to the skeet field and I'll report back.