Mystery Rolling Block?

by Charles, Thursday, July 11, 2013, 09:13 (4157 days ago)

A friend picked up this very poor condition Rem. RB and asked me to ID it for him. Here is a pick of the rifle and the markings on top of the barrel at the breech. I stuck a caliper in the muzzle and the bore is about .459 or so.

This appears to be the original configuration. Anybody have a clue what this is?