I understand the whole mess is fairly complicated but what I'm after is what the proof house actually stamps the guns. My 2-1/2" damascus gun was nitro proofed and stamped 850BAR but my gunsmith was speaking to Kirk Merrington and they seem to think that 850BAR is also the proof for 2-3/4" guns which, according to Dr. Bill above, can also be proofed at 1150 BAR.
I'll be using the lowest pressure loads I can find anyway, right now I'm more interested in what guns should be stamped rather than actual numbers.
I have an email in to the Birmingham House, I'll see what they say and report back.
Just found this in the .pdf from rocketman by way of revdocdrew.
"In 1989, all proof data was marked in metric using the bar as the unit of measurement. The use of kilograms per square centimetre was dropped. Under this system, 850 bar represented standard proof, with 1200 bar being special or magnum."
