Is it the head or plastic or both that causes the issue? I've read where at the end of the life of old gunmakers' chamber reamers because of wear and resharpening, the tool is slightly smaller in diameter and reams smaller chambers. I read it on the internet so it has to be true. Google "Polishing shotgun chambers." There are several videos on the simple procedure using a chamber brush, fine steel wool, electric drill and oil. Might be worth trying, but it maybe the old chambers are a tad too tight and worth doing something to correct the issue. Good luck. Gil
