Note that while the piezo-electric pressures should be interchangeable anywhere as they are true pressure the crusher pressures are not universally interchangeable.
The British & the US did not necessarily use the exact same set up for taking crusher pressures, therefore should only be compared to their individual set up. The same load which measured 3 tons (6720 lbs) my well have not read 6720 on an American crusher gauge due to the different set-up. The formula cited was thus good "ONLY" for British crusher pressures, though the conversion to psi would be good for US guns.
