- re: barrel making.
I am sure the barrel maker would do anything as asked: barrel length, width at the breech, weight, rib extension, type, length and width of lumps etc. However, it was his responsibility to have the barrels assembled and provisionally proved.
This was done for sure by the best vendors such as LB or DD or Jean Breuil or Heurtier (who did braze their ribs..).
Some vendors might have provided individual barrels upon request.
And of course Granger did everything himself AFAIK.
- 65mm was the mainstay at least until WWII. Pigeon guns were different of course. I would say that 70mm took off well after WWII for general usage. 67mm was and still is also an option at least for the ammo. Again I'll look in the MF catalog to study the trend.
- it would be fun to call the "banc d’épreuve" and ask! That would be amusing for sure. There most likely was some paperwork associated with that, but I doubt it showed up on the "journal Officiel". And if the paperwork still exists in St-Etienne , it is buried way deep in there...
Best regards,
WC-