Never mind, found it. The pictures are too poor to tell much, but that is not a cartridge chambered in the current Merkel line. It looks like a fairly typical Mekerl 140 style boxlock. If so, and if post war, it could either be a custom chambering or a rechamber, although why rechamber for that cartridge is beyond me. I can't find a 450 #2 in any of my pre-war catalogs either. NECG might have more information, but as the pictures seem to show what may be a gun in less than pristine condition, and you can get one in a 470 of 500NE for under 10K, why bother with this one? Dave