Sorry to be so long getting back on this, but this software is so slow to operate that I visit less often, so I'll have more time.
The rifles you (and wiley g, at the bottom of the postings) refer to are (or were; I don't think they're around any more) from RMAC (Rocky Mountain Arms Co., Salt Lake City) and were in the Black Powder Gun Digest, Toby Bridges, ed., 1972. The owner of this enterprise was Richard J. Casull. The rifle came in several calibers, was a breechloading black powder arm, and, as far as I know, was never very successful, economically. How successful it was mechanically, I have no idea. There was a rotating "turret" behind the barrel, which, when turned, exposed the chamber for powder and ball. Rotating it back sealed up the system and placed the chamber in line with the barrel, which was a tad undersized, with a "forcing cone". This provided a good gas seal and ball-to-bore fit. A percussion nipple and centrally-hung hammer completed the system.