First, I would look at the country of origin of the proofmarks and the length of the shotshell. Then see at what charge the tubes were proved. And then try to generally equate(lean toward the lower values) the pressures of blackpowder and smokeless. Sometimes light smokeless shotshells have a pressure issue.

Kind Regards,

Raimey
rse

Last edited by ellenbr; 09/14/07 07:43 PM.