Dogfox and GregSY continue to parrot the 'conventional wisdom'.
The funny thing is that this 'wisdom' is backed up by nothing other than people/gunwriters/shooters repeating a lot of faulty information for 5+ decades.
I have a series of articles published in the American Rifleman in the 1930's during the establishment of the SAAMI standards. Many comments concerning chamber length, all saying it was basically irrelevant. PRESSURE is important and case length only if it has an affect on PRESSURE.
The reason for those warning on shell boxes is that with the establishment of SAMMI standards the service pressure for shotshells was increased dramatically compared to earlier shotshells.
