I just bought an old Iver Johnson 16 gauge single-shot shotgun and have no idea what the chamber length is. I plan on using 2 1/2 inch light loads, but would like to know if it is a 2 3/4 inch chamber just in case I needed to use one. I have read a lot of posts about having a gunsmith check it and I would do that if I had one nearby, but wouldn't it be a reliable test "if a fired 2 3/4 inch 16 gauge empty hull will seat in the chamber and lock-up without crimping the end back down any." Thanks