Looking for an iddentification on an unusual action described to me by my son. He saw it at a market, but of course he did not get a contact, take photos or even write down all the markings.

I have not seen this gun, not even pictures, but I think I have heard of or seen a simlar action in the past (getting forgetfull obviously, it sounds familiar but I can't think where from).

This gun appeared to be rifled and about 20 bore. It was dated 18?? and had a ramrod (or maybe cleaning or stacking rod?) The rod makes me think it may be an early cartridge conversion, but I am not sure.

The breach is opperated by rotating the breach block. I immediately thought of the hinged Snider conversions, but the person describing it says definitely not.

The breach block has a long angled firing pin running through it and is fired by an external hammer (Snider-like)

The breach block is cylindrical and considerably larger in diameter than the barrel. It is mounted on an axis pin below the barrel, similar to a revolver cylinder.

To load it is rotated about 90 degrees to align a loading ramp with the barrel. The breach block is then rotated back to close the action.

The stock is decorated with inlay, maybe bone or something similar. This puts me in mind of the good old Kyber Pass, but not having seen it I am not sure.

The only marks described are a Crown on the barrel near the breach, and a date (described as 18-something). Other marks may be present but were not noticed. The overall condition was described as "prety rough", with a fair bit of rust and crusted dirt.

If anyone has any suggestions as to a maker or style for this action I would appreciate it, the price seemed fair given the condition, but I need to send pictures to my son and get a better idea of what I am going to look at. I have just got back from visiting him, and I take longer to recover from 1800 mile round trip drives these days, must be the heat.