I just picked up a pretty neat rolling block rifle. It is unmarked, except for a "5" on bottom of the barrel and receiver tangs and "45CAL 60GR" on top barrel flat ahead of receiver. The barrel is 30 inches long. It looks like a Whitney, but lacks the "roundness" of a typical Whitney receiver. In fact, the receiver is an almost exact copy of the Remington Number 1 sporting rifle, other than the typical Whitney-type block and hammer pin retainers. The receiver is nickel plated and shows considerable wear to finish around trigger guard. It has beautiful wood, obviously refinished, and a brass buttplate. I remember seeing a Whitney carbine in .50-70 with a brass buttplate at one of the Baltimore shows.
Any thoughts? I can provide pics.