Drawing of a P08 barrel

[Patrick Chadwick]

Connoisseurs of thread sizes will note that the barrel thread is WHITWORTH form thread and 20 tpi, although the external diameter is 18mm. This appears to have been a general Mauser trait - the threads for both large and small ring Mauser rifle actions are also Whitworth threads,regardless of the diameter. So anyone strangling a new barrel cut with a UNF thread form (60 degree included angle) into a Mauser action is making a nonsense of the whole concept of thread fitting. The difference in the included angles will mean that the male and female threads will only contact at the bottom of the UNF thread. If the barrel is tightened up to the same torque as for properly mating threads, then there will be a huge shear force and considerable distortion of the mating faces along the thin line of contact.


Patrick