Sounds like an conversion of an 1853 Enfield - the 3-band Enfield rifle.

Later-on, some were made purpose-built, but if the lock doesn't have the spring-catch-lock, it is probably a conversion(I think).

Bro has a couple Enfields - one early 2-band, one later 2-band.

Pretty neat, actually - Buffalo Arms & maybe trackoftheowlf has brass if you have a mail box States-side.

The Dominion brass is about 1/4" short so it would fit the US .58 Carbine of antiquity - very rare today.

There was a good Snider article in DEc. "Handloader"