With all this primer seating depth talk, I decided to FAFO with my loads to see what it's all about. The error factor of the calipers can be +/- .001 since that was the ave range of variance I saw taking multiple measurements, so the absolute measurement might be off, but a look at the relative measurement I think still gives some value. I seated with 21st Century hand primer with micrometer deep as possible/to full stop with as much force as I could put on the thumb lever, spun the case and hit them again for full on max depth. Measuring the batches after seating, I got depths under the case head of .007-.012 using what I gathered to be equal pressure and depth seating. (Yeah, there's a range, eh)
Alpha primer pocket depth: .130
WLR cup + anvil: .127
Doing the math there, .003" under the case head is the anvil touching the bottom of pocket. Anything beyond that is the crush. So in batches I made there reveals crush depths .004-.009.
Here' where things get weird. So I have different seating depths, starting at .004 crush and ending with .009. Everything fired same as usual with no discernable difference in groups ES/SD in a hasty test session, except the .012 depth/.009 crush rounds. Light strikes, no fire.
Measuring the removed primers after firing, the light strike, .009 crush primers measured .118.
All the other crush depth batches had no difference in heigh between them all in the .004-.008 range, and still measured .127.
So the big questions are: (Appealing to outside critique here)
1. With the different crush depths (supposed crush) why are all the primers the same height after fired? Shouldn't they be incrementally different?
2. Did the actual crush depth not begin until it was too much with the .009 depth seated primers?
An extremely rudimentary test, yes, but it's done with tools & methods an average hand loader has at his disposal. I intentionally went heavy & hard on the seating for this test to see if my previous statements "Just seat them till full stop" had merit.
Only preliminary conclusions I can make before outside input:
Regardless all the data and testing whether accurate or however inaccurate, primers will seat to different depths with the same "felt pressure" of my 21st Century tool.
One can crush a primer so hard to render it ineffective. So, my previous statement to just seat to bottom and go can't be applied universally. Dunning-Kruger bit me there. LOL
If I was truly getting the crush depths by my measurements, the range of crush up to that ineffective crush/seating depth, has no effect on performance.
Alpha primer pocket depth: .130
WLR cup + anvil: .127
Doing the math there, .003" under the case head is the anvil touching the bottom of pocket. Anything beyond that is the crush. So in batches I made there reveals crush depths .004-.009.
Here' where things get weird. So I have different seating depths, starting at .004 crush and ending with .009. Everything fired same as usual with no discernable difference in groups ES/SD in a hasty test session, except the .012 depth/.009 crush rounds. Light strikes, no fire.
Measuring the removed primers after firing, the light strike, .009 crush primers measured .118.
All the other crush depth batches had no difference in heigh between them all in the .004-.008 range, and still measured .127.
So the big questions are: (Appealing to outside critique here)
1. With the different crush depths (supposed crush) why are all the primers the same height after fired? Shouldn't they be incrementally different?
2. Did the actual crush depth not begin until it was too much with the .009 depth seated primers?
An extremely rudimentary test, yes, but it's done with tools & methods an average hand loader has at his disposal. I intentionally went heavy & hard on the seating for this test to see if my previous statements "Just seat them till full stop" had merit.
Only preliminary conclusions I can make before outside input:
Regardless all the data and testing whether accurate or however inaccurate, primers will seat to different depths with the same "felt pressure" of my 21st Century tool.
One can crush a primer so hard to render it ineffective. So, my previous statement to just seat to bottom and go can't be applied universally. Dunning-Kruger bit me there. LOL
If I was truly getting the crush depths by my measurements, the range of crush up to that ineffective crush/seating depth, has no effect on performance.
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Not sure why you crushed them so much.
