KY Jon, I can't answer that. I know the proof was specified in terms of maximum load of shot. Pressure was not specified. I assume at that time (late 19th, early 20th century) it was difficult to measure?
There wasn't the same interest then in 'pressures' or 'velocities', perhaps because they were difficult to measure?

Last edited by JohnfromUK; 02/02/14 05:05 PM.