I have one of the Nepalese guns. As has been said, they generally aren't as bad as they first seem...at least once you've scraped off a century's worth of dirt and congealed yak grease.
One thing worth noting. I've heard this from a couple of sources online and one my instructors who's done a fair bit of M/H work over the years, so I'll pass it along. Supposedly the receivers for the Nepali guns were built under British supervision, so they're generally not bad. They aren't quite up to the standard of Birmingham steel but they're better than might be expected.
The barrels, on the other hand, were contracted out locally. Most (if not all) were forged by hammering together multiple strips of metal around a rifled mandrel. As it happened, these weren't shot much on account of the British being wary of over-arming their subjects. Not until the .577/450 was regarded as obsolete did appreciable quantities of cartridges make it over, by which time it was discovered that the barrels had a bad tendency to split.
Could just be an overabundance of caution. Could be justified. Personally, I wouldn't chance it. With a British rifle, sure. With a Nepali copy...not so much.
Mine was beat-up (and cheap) enough that I've got other plans.
At present I'm looking to put on a 16-20" barrel and rechamber for .45 Colt. From the look of things it's feasible - but I don't know that I'll have the time this semester to get it done and, God willing, I graduate in May. This may be a somewhat longer-range project than expected.