Gentlemen, if you Google M1803-41-51 Click on the site" Digitalt Museum And follow your nose and the 1803's (about ten or so) and I looked at a couple/ look exactly like the one I have. Even some of the stampings are the same (OIR on one of them in the same spot on the barrel) the K and the crown the shape of the lock,the stamped number and the brass are all the same. I polished the brass on mine and when I saw these pictures I almost fell out of my chair. The Danishrifle 1803 may not be as rare as the 1821 but I think it is what it is. Let me know what you think (Patrick, Claven, gew, and anyone I might have left out) all your opinions are valued.