Mr Berg, Welcome to TFL.
Can you please take a good photo of the lock side faceplate showing hammer, etc.? You stand a better chance of identification if there are any markings there or at least someone can note similarities with other percussion and/or modified actions in that manner.
and again, welcome. A lot of people here know a lot of useful information (I'm not one of them mind you
Youth rebels, age conserves; between them, they advance. The Marines will cease to win battles the moment either camp achieves ascendancy. – Robert Leckie, Helmet for my Pillow