Years ago when I lived in San Francisco ,these wre quite common in second hand stores, converted from 450 Adams to 45 acp These were originally sold to guys going to the Klondike as a means of protecting your Gold and being concealable as the NWMP sort of frowned on pistol packing yankees even back then.The converted ones came about during the Vietnam war as there was a high demand for anything concealable.Now that I live in the Yukon these are seen in a number of collections here. When the action is open give the muzzle a sharp rap with a rawhide hammer Inside are Belgian proof marks. Hope this helps. The posts about converted shot guns, not being an antique, I find very misleading. I guess in the age of the internet not having a clue what your talking about still makes you an expert.