It really is an art compared to more modern options, mostly due to trying to replicate what a skilled operator at stamped metal factory at the time was capable

It really is an art compared to more modern options, mostly due to trying to replicate what a skilled operator at stamped metal factory at the time was capable of at a small scale. That and the press fit barrel and gas block are much trickier than just torquing a barrel nut to the right amount of ft/lbs. like with the AR platform. Enthusiasts will pay eyebrow raising amounts for custom ones from a shop with an impressive reputation for something that was the height of 1950s technology.