Two 2" action flats courtesy of L.D. at Westley Richards Agency, U.S.A.
The first is one of a pair H&H Royal Centenary gun made in 1935; with the standard 1925-1954 proof marks, for 1 oz.
In 1935, the Proof House determined the 2” “cartridge loaded with full 2 1/2” charge...proof of the 2” gun should be identical with the 2 1/2”’.
I don't have the pre-1954 12g 1 oz. standard or max. service pressures
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/Proof-Marks/i-X9f76wd/0/d3e7b0bc/L/WR%202%20inch%201935-L.jpg)
The second is a H&H Royal Twelve-Two, completed in 1934, just before WR changed the name of the 2" guns. The gun was rebarreled in London in 2006 with CIP Standard (Crowed STD) proof.
![[Linked Image from photos.smugmug.com]](https://photos.smugmug.com/Proof-Marks/i-ggWNnPX/0/daceaa9a/L/WR%202%20inch%20CIP%202006-L.jpg)
The
CIP Standard 2" pressures are same as 2 1/2" and 2 3/4"
Maximum Average (Service) Pressure 740 BAR = 10,733 psi;
Maximum Statistical Individual Pressure 850 BAR = 12,328 psi
Mean PROOF Pressure 930 BAR = 13,489 psi