Maybe, with such equipment you'll get readings you wonder about. In that time electronics were in a early phase of development, and research uses every device available on the market. When I was student in the sixties, I was involved in such test equipment and we all including our Prof. were not able to interpret every observation correctly.
The 20 KHz low-pass filter is standardized (mandatory) by CIP (and also by Mil-Specs and SAAMI). With this you will see every important spike on the plot. And those artifacts shown in the sketch may be possible with artillery cannons where the barrel time is longer than the speed of propagation of waves traveling back and forth, but not with rifles and handguns.
With rifles one may observe erratic pressures, because of poor ignition, having SD about up to 50% in pressure readings, but showing low SD in velocity. We see dependencies, but cannot predict this phenomene.
Please note: do not trust every publication, in former times it was scientifically proofed that Earth was a disk !
Last edited by h_broemel; 01/21/08.
