Hello - I recently purchased what seems to be a lightly used 12 gauge LC Smith Ideal Grade from an auction house. The action locks up nice and tight, and doesn't seem to have a lot of wear. Overall, the gun is in great condition. However, it has an issue where the action will not close with a shell in the left barrel. The issue is the rim of the shell is too large to fit in the chamber cut rim. I put a micrometer on it and it is tighter than SAAMI specs, which I understand may not be totally relevant given the age of the gun. However, I wanted to understand the measurements. I've tried several types of shells in the chamber to see if that would make a difference. My reload Win AA are too large, so are factory Federal Top Gun and factory Win AA. Remington STS is the smallest diameter of the 4 I tried and could be pushed into the chamber rim allowing the action to close, but are still way too tight and not consistent enough in dimensions to be repeatable. Note, in case you are questioning my ammo choices, I don't plan on shooting factory ammo in this particular gun. Going to stick with same reloads I shoot in my Flues. Gun is chambered 2 3/4" and the shells I've used are regular 2 3/4".
What I'd like to understand from those in the group are is anyone run into this before and am I correct in thinking its the cut rim diameter, or could it possibly be something with the extractor? Is it a simple fix for a competent gunsmith? Is this a common issue with LC Smith shotguns, or did I win the lottery with this one? Thanks in advance