I have had a casesing swell up on me and get stuck in the breech in the past which is what I suspect has happened to your gun as well. I wrapped mine up in a real good rag and locked in down in my vice. After a few blows with my deadblow hammer it came loose and allowed the slide to come back to the rear position again and spit out the old cartridge that was jamming it. You might wish to try squirting some oil on the slide area's 1st to help loosen it up as well.