Gunsmithing knowledge?

[Aaron Beck]

Appologies for a very brief introduction. I was an interested and somewhat active forum user about 10 yrs ago when I was hunting with a 10 ga hammer gun. 1884- l grade, perhaps I sold it to one of you.
I recently got the bug again and have landed a 16 intended for the Maine woods. I was casting about for a gunsmith in Maine who might advise me during the minimal 3 day inspection but didnt have much success. I did speak with Steve Dalzell who was willing to assist but is on the other end of the state, so I am presently weighing things on my own. I wouldnt shoot this without more info, but as the time is ticking... rst loads if it comes to that of course.

I will attempt to post some photos, but generally the thing ive noticed which is most alarming is at the breech face of the barrels. It appears to be a slightly upset ring of metal where the rim of the shell rattles around on firing. There is also evidence of an outer ring near the barrel od.
The chambers measure .745" and so are somewhat oversized. A regular rst shell does have free play in the chamber.
Im not sure how well the photo evidence will transfer but please have a look and let me know if this is a major red flag. The gun also exhibits some fracturing in the wrist which was known when I bought it but could also speak to heavy use.
Additional photo of green leaching from solder on barrel flats, barrels ring ok.
Thanks in advance