Another thing we discovered then was that his carbine appears to be a copy (Afghan or whatever) rather than a British-made Martini-Henry ... and I think his bore diameter may be a bit undersized, if I recall correctly ...
I think I've read that the Nepalese made Martini Henrys have around a .458 bore, as opposed to .468 for the British made.
Edit: Yes, that's a cool picture with Gary James firing his Howda- but keep in mind he's using reduced round ball loads for shooting the stages, those weren't bad at all for recoil. He did bring some full power loads with Minnie bullets for us to try out-muzzle rise is pretty significant with those! And, if you "go modern" and try to hold it with both hands, the opening lever under the trigger guard can be a real "knuckle buster"!