Burrard did very litle testing of his own outside of pattern testing. What he did was report on tests conducted by some of the major testing facilities available in england of his day. Prior to the final revision of his book quite extensive reports of testing done with Piezo Electric instrumentation was given. It is quite worthy of note that more modern equipment has verified the accuracy of these well conducted tests from the past. There will of course always remain the difference in pressure readings of those taken with crushers & those taking by the PE tranducers. As I recall most of Bell's testing was done with strain gages. Any of the three methods can give reliable & beneficial results, but not necessarily directly equivelent to the others. Only the tranducers as I understand it give a direct & exact reading of the pressure inside the bbl.
Personally I am not questioning the equipment used by either. Simple fact is the testing done by the British with the introduction of the fold crimp shell was far & away more extensive than that done by Bell. What I question is whether he in fact did extensive enough testing to actually isolate thos 1,000+ pressures as to be caused by the hull used or whether other factors were involved. In any pressure testing there will always be variable readings. I do also recall that he tested some of his "Low Presssure" 3" shells in a nominal 2˝" chambered gun. If I recall correctly these loads did increase the pressures by some 1,000+ pressure units, what ever units he was reading. This is to be expected as in this case the crimp of the shell is actually being pushed into the cone prior to firing, a factor Burrard Strongly discouraged. I will take Burrards recommnedation here anytime as this practise definitely increases the resistance to the opening of the crimp.
I forget the name now but I once read a balistician for a major ammunition co make the statement that he could vary the pressure reading over a wide range with no change at all to the load except to the crimap applied. the tighter the crimp, the higher the pressure. Shells should "ABSOLUTELY" not be fired in which the loaded length of the shell is pushed into the forcing cone.
