Scoony,
The back of the chamber should measure .473 which leaves you 3 thousands clearance... brass springs back 2-3 thousands so that means your other chamber is normal.
Given you scratch marks are circular ...
I would look inside the remy for a bur around the entrance of the barrel - it really shouldn’t be a tight chamber, but reamers do wear down over time so that barrel may have been done when the reamer was simply wore away to small.
You can take a finish reamer and “Lightly” touch it up, but normally I put it in a lathe to do so.. - first I’d look at it with a bore scope to see how well the chamber and bore are aligned then I’d slug the bore to see if it’s good or not...
I pick what barrel I’m going to keep by slugging, and checking chamber alignment with the bore - and of course shooting it.
So is that a .470 base fired shell or a new one - I’d check to see what a new one does as well .467”
Last edited by Spotshooter; 10/19/20.
