I just purchased a TC in 44mag/410 with external choke. Serial number puts it being manufactured in 1970. It does not have a scrach and does not seem to have been shot more than a few times. I removed the choke to shoot a few 44 mags. After a few shot I noticed the shells are bulged at the rear and one of them was split. Is there something I'm missing this does not seem right to me? The 410 shells fit great but the 44s seem a little loose but thats what the barrel says. If you can help let me know I do not have a owners manual. Thanks Chris,