Hey unclenick--thanks for the clarifications--I remember those traces from Jim's site-- as I recall he used a 30 06 trace from a very well known manufacturer as the example for the secondary spike recorded. Since the gauge is intended to measure material expansion at the chamber proximity--is it fair to say that the pressure spike might be significantly higher than what the trace indicates? In the dim recesses of my scrambled mind I also recall having a discussion with Jim about a "P pulse" wave phenomenon upon ignition--a pulse wave that goes down the barrel to the muzzle and back again to the chamber as the bullet leaves the chamber.
It's been a while since I've hooked up my system--I've been trying to get ready for hunting and also spending (too) much time trying to figure out the 224 valk thing.I need to review and refresh my memory.
I once had a powder that had sat on my shelf for a while (and was actually already a pretty old lot when purchased on-line) produce pressure warning signs in the handloads I had fired that were well within charge weights listed in the reload manual. I erroneously assumed that in general when a powder degrades --among other things the powder efficacy degrades. I called the powder manufacturer about this--and was told for the particular powder I was using that in fact that energy yield could go up upon ignition as a result of degradation for the particular powder.