[Wilmurt]

I've come across an affordable 1884 top lever with 30" twist IC/Mod barrels. My interest is to use the barrels on my current 1887 D3 top lever which has original Damascus 28" Cyl/Cyl barrels. Both are size 1 frame but of different grades. The forend seems to be in good condition and will mount barrel/forend on my gun to check fit. Which, if purchased will have qualified gunsmith check out. The only tools I look at the gun will be choke and chamber gauges and probably won't be able to go to gunsmith to check wall thickness. To visually check the condition of the barrel what should I be looking for? What is "barrel ring", which I've heard used on this forum? How do you judge the amount of pitting in/out of barrel considered "normal" for a gun this age? All insight to what I should be looking for in a usable barrel would be appreciated. Thank you