If your SX3 is anything like my SX2 was, the problem is probably with your action spring plunger or as some call it your recoil spring plunger. It's the plunger that goes down in the stock of your rifle that ejects the old shell and puts in a new one.If it gets grimey your gun will jam all the time. The problem with it is, they sometimes come from the factory with to much oil, grease or whatever and they collect dirt. They are a pain in the butt to get clean but your gun should work fine after you clean it. I'm like you though, I'd sell that gas operated gun and get a inertia shotgun in a heartbeat. Nowhere near the pain in the rear as a gas shotgun.