Skeeter, I can't confirm the tons values in psi either. I can do that with the later 850 bar proof/650 bar service pressure guns (crusher figures). Got it straight from the Birmingham proofhouse that the 650 bar figure is actually 740 bar transducer, which is the source of that 10,730 psi service pressure figure for CIP standard proof guns, for the last 25 years or so. Things were confusing during the "tons" era because the Brits marked their 2 1/2" guns 3 tons and their 2 3/4" guns 3 1/4 tons--which is only an 8.5% increase in service pressure. That's not nearly enough to make the jump from standard to superior/magnum loads. But . . . if 3 tons does actually work out to 10,730 psi--although I'm not sure it does--then 3 1/4 would be very close to our SAAMI service pressure of 11,500 psi. And those 2 3/4", 3 1/4 ton Brit 12's were marketed in the states. Mostly Webley & Scott 700's.
Yet another area where things are a bit murky.
