doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Spanish Paper found in old gun case

I don't know when the Proof House started issuing the certificates; possibly when the Belgian Proof House did in 1924

In addition to Ted's information, the bores are 15.9 mm = .626"
Right choke 15.6 mm = .614"
Left 15.2 mm = .598"
It was proved at 900 Kg/cm2 (most 20s were proved at 1000) which would be for a max. service load of 10,500 psi

They changed the certificate in the 70s under CIP
The chokes are indicated by * (Full) and *** (Mod)



And again in the 80s. A 12g with 3" chambers proved at 1000 Kg/cm2