Considering it has a straight stock, game bird scenes and barrels with different serial numbers to the action I would suggest it was a shotgun originally, probably 20 or 16 bore and a set of barrels have been made at a later date. Having said that it is still very nice as the proportions of everything look about perfect. If it was in 375 Flanged Magnum instead of belted I would be more than happy to own it.

Matt.