As I recall, the reason for the reputation for unreliability came from using nitrate film stock, chopped up, to make propellant for guns. Rebels used to raid movie theaters and steal the flim to make ammunition. Needless to say, it was not a very progressive propellant. I would keep the gun in its original condition. It was probably totally handmade. In the early 80's, Guna and Ammo had a series of articles on guns of the Khyber region.