You do an excellent job with the resolution of the pics Geoff
The original proof was 1925-1954
Reproved early 2005 before STD, SUP & STEEL SHOT were marked, and the date code was changed to numbers ie 0 5
It was proved at 1200 BAR = 17,400 psi for a max. service pressure of 1050 BAR = about 15,230
The original bore 13/1 = .719" - .728". 18.7 = .736"
Bland 1954 catalog repro
https://cornellpubs.com/product/2862/Maybe Bland's Brent Waterfowl Gun
https://www.shotgunworld.com/thread...utm_source=google&utm_medium=organic
