I never heard of a 'non military' Snider before as well!
It does make you wonder when it was converted, perhaps a date on the barrel / proof mark will determine that?
I know this will be BP only, but it certainly is a unique piece rigbymauser........no wonder it caught your eye - I really do like it as well.
The workmanship is superb!
Certainly a wonderful pickup, you must endeavor to get this old lady up & running, it will be marvelous to see what caliber it finally is, the load data; but most important how she shoots!