That looks like what IMA is calling the Brunswick P-1837 Full Length Percussion Two Groove Rifle in .75 cal
, but with a different hammer and no escutcheons. (Unlike your .670 version, neither of the two that Norm Sutton rebuilt for them
have escutcheons). The Brunswick P-1837 type Percussion Two Groove Rifle & Bayonet: Untouched
has your escutcheons, and the parts guns
they are still selling appear to have the same hammer as yours. The Nepalese Brunswicks described by John Walter on page 32 of Guns of the Gurkhas
have different escutcheons, with finials held by screws rather than nails like the missing ones on the IMA parts gun.
Have to admit that my skills (sic
aren't up to the task of making or rebuilding the fancy patch box, so I copped out by getting one of the late model smooth bore "Brunswick" muskets, (which also lacks the distinctive trigger guard), and has yet another
type of escutcheons, rectangular rather than oval, but held by nails.
My sense is that there was a great deal of experimentation involved in the making of these early Nepalese pieces.
Some of the numbers/letters on yours are pretty hard to decipher - maybe our Nepali expert Beoram can help out. The numbers on the rear of the bayonet lug are the serial number IIRC. How about a pic of your bayonet?