I own quit a few guns with screw in choke tubes and my SBE is the only one I've ever had get a stuck choke,and I know of four other people with the same thing.I believe it came from shooting BB steel out of it.I had mine removed,they had to cut it out.Every year I get a new choke for the gun because the one I had in the gun will swell up and is hard to get out or get back in,and it will not even fit in the end of my nova.That's just my experience.