Against my better judgement I'll re-enter this thread. The first big issue is the alledged measurement. In the radial plane we are utilizing measurement of 1 / 1000th of an inch increments. along the bore we discuss about 12"??? pressure drops significantly after @ 9"" and the difference between 12 and 16 inches could be significant. Until we have data that states xx.yy" from the breech at the 7 o clock position an area of 0.xxx
thickness was found we are speculating. Heres my speculation.
If you use pressure curve based on V. Drake's paper to the Journal of The Forensic Science Society of 1962 as the basis for proof pressure, factoring in mean vs max, lead crussher vs piezo and the current 30% overload a cylinder of .730 ID vs .762 OD would require a yield strength of 80,000 psi material. Modern steel can easily exceed this so it would be feasible for this gun
to pass proof. It is not beyond the bounds of probabilty that the proof marks are legitimate. If the wall thickness is greater than .016: or further out than 12" the ability to pas proof improves and vice versa.
EJ all things being equal .040" at 9" is sound, below that I'd get written consent from the owner before submitting to proof.
