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Unread 04-13-2002, 10:29 AM   #19
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Default Re: British Markings, proof pressure

I can through one bit of light on the pressure question. In the US the CUP unist of pressure was measured by a copper crusher and piston in a small hole in the chamber side acting in the radial direction. In the UK the pressure was measured with a crusher behind the breech face with the cartridge case lightly oiled. Thus the British system measures the back thrust. The two systems yeild different numbers and the US system typically yields a bigger number than the british for the same load.


These days in the US they use a transducer for direct PSI measurements and get still a third and higher yet number.


In years past the British proof house marked the gun with the working load and no indication of pressure. Hence my question, when they mark the pressure, is it proof or working pressure?


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