I'm new to the big bores and hope you experts can help. I bought a single shot hammer rifle yesterday and I'm confused as to what cartridge it takes and who made it. I didn't have much time to check it out before I bought it. The place I bought it at described it as a 600 Swiss, but I can't find any indication such a cartridge exists. I'm on the road and haven't cast the chamber, but I made a few measurements with a micrometer. The diameter of the 8 groove rifleing is about .5745" (14.59mm). The chamber to the rifleing is 1.65" ( 41.9 mm). The rim diameter is around.74" (18.76mm), and the base is .66" (16.74mm). The bore is in great shape. I think it may have a tapered bore. Does this make sense to anyone? Would it be a shortened .577 Snider?

As far as the rifle goes it has no letters, numbers, or proof marks on it. It seems to be very well made, with double set triggers, one fixed and one flip up v notch sight as well as a tang sight. The heavy 28 3/4" barrel is octagon with a hooded front sight. There is a sling attachment on the barrel and a button to attach it to on the stock. It opens with a Lefachaux under lever. The straight stock has a cheek piece and inset trap. The engraving is nicely done open scroll, with nothing unusual except for on the trigger guard. There are some musical instuments, french horn, drum, another brass instrument in a group with a couple of halberds sticking out. The surprising thing is there is a book open on top of the instruments. I had to use a 30X illuminated microscope to see it, but it is a music book with a couple of lines of musical notes engraved on each of the .11" tall by .19" pages. LOTS of case colour and blueing on it. All the metal was heavily varnished(?) and intact except on the under lever. Anyone with a guess of what country would make a rifle of this style?

I was hoping to use this to hunt game up to the size of moose, but with the short cartridge I guess it wouldn't have the power. Would lengthing the chamber to Snider or slightly longer length be a good idea? Thanks in advance for your comments.