"Lucretia" would probably be a 2nd Allin conversion of the Civil War muzzleloaders known as the 1866 Springfield. The first Allin conversion was a .58 rimfire. The '66s used a sleeved barrel to reduce the caliber to .50, and used the .50/70 centerfire cartridge. I have one of these, and have shot it from time to time. It certainly was a good Bison cartridge in its day. By the way, I think the picture is reversed; it apparently shows the hammer and lockplate on the left side of the rifle, and I'm pretty sure no left-handed versions were made!

By the way, "Buffalo Bill" never shot a buffalo in his life. Bisons, yes, Buffaloes, no.

John

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- Cogito, ergo armatus sum -