Quote:
steve4102
Has anyone ever done pressure testing to determine at what pressures the most looked for pressures signs actually occur?
For example, stiff bolt lift, is there any test data that shows at what pressures the case expands enough to cause the bolt to be stiff? How about loose primer pockets, any idea at what pressures a round is running at to get loose primer pockets after a few firings?
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Staying inside the world of Quickload predictions, I can predict what load is at the threshold of loose primer pockets.
The 1889 Mauser case head built with a large primer pocket is common to cartridges I have overload worked up to the threshold of loose primer pockets: 243, 257RAI, 260, 270, 308, 30-06, and 8x57mm.
I have rifles, but have not done it in 22-250, 250 Sav, 6.5x55, 7x57, 300Sav, and 35W. I expect that I could predict the threshold of loose primer pockets in these cartridges within 2% powder charge. That assumes that I have used that jug of powder in another cartridge where I knew the threshold. That also assumes I have the feed back of a lower pressure round that the chrono velocity matched the QL predicted velocity.
a) For an individual hand loader of a 45 Colt revolvers with thin chamber walls, we care what the pressure is relative to what pressure that revolver is known to tolerate.
b) For selling 308 ammo, we care what the pressure is and how that relates to how the 308 was SAAMI registered.
c) But for an individual hand loader of 308 ammo for his strong rifle, the pressure does not matter. The threshold of the effects of pressure are what matters.
That third case is where the QL predictions are useful to speed up load development. The system is precise, but not accurate. At least we cannot trace the accuracy to the NIST, so the accuracy is as meaningless.
Today I made a sound peak detector for guns. I am working in miliVolts not db re ubar. All I need is precision [not accuracy] to plot the SPL and find the inflection point for the threshold of super sonic gas escapement.