Considering some version of lapping a Lee Enfield barrel?

[Eaglelord17]

Meanwhile, in the Khyber pass a goatherder in a yurt is pounding out SMLEs with a forge, hacksaw, hammer and manually powered rifling machine made from bits and pieces of a GAZ-69.

Depending on crude people want to get, if there is a will there is a way. You can literally rifle a barrel just using a cutter (on a long rod), some lead, and another barrel. You line both barrels up basically nose to nose. You then pour the lead into the other barrel with your cutter in the middle. The lead works as a guide and it will guide your cutter to make a duplicate of the barrel with the lead plug whatever the rifling on that barrel is. Lots of brute force and ignorance required for that as well as patience. Takes a very long time from what I read on it, generally at least 8 hours. You also have to cast the lead multiple times. Basically no one does it this way anymore, but 150 years ago this was a option available to the gunsmiths of the era.