Many of these Turner Kirkland treasures were later production muzzleloaders made for trade to native peoples in Africa, and South America. They are sometimes referred to as monkey guns, since that is the game they were often used on. And, as was mentioned they were not first quality. In fact count yourself lucky to have gotten one with proofs. I bought scads of these in the early seventies, and only got a few that were proofed. That being said a friend built a canoe gun out of a 27" Kirkland 20 gauge shotgun barrel, with no proofs. That not only survived a load with an air gap between powder, and shot, that bent all the barrel pins, and the upper lock bolt, and popped a piece of wood off the end of the tang inlet, but after careful refitting, and reproofing, served him for the rest of his life.
Hungry Horse