My gun is about 7-8 years old and it has been flawless until this year. After shooting a 2 3-4 #7 shot (1500fps) the action jammed shut. It would not eject the shell. I could not get it out until I took it apart and beat the end cap several times to un-jam it. I cleaned it and got the action working again and went to shoot it again and the same thing happened. I called and the rep said it might be the rounds I am shooting bc they are low but I have been shooting the same thing out of my gun for 7 years. Any suggestions?