with the caveat that condition is everything, the Birmingham guns were made to be shot and made to last. There's not much that can go wrong the action that can't be fixed easily by a competent gun smith. Some good advice by previous posters.

I shoot an 80+ year-old Westley Richards box lock. I don't shoot near the volume as you (mid-hundreds would be realistic), but my gun still functions flawlessly with minimal maintenance. I also shoot RSTs. I've watched WR boxlocks on the market and notice their price fluctuates quite a bit from bargains to rip offs. \