Little about primers

I'll play! Everything you ever wanted to know about primers:

Google: Primer Info & Chart + Milspec Primers for Semi-Autos & Other Primer Applications

Smiles,

https://www.aardvarkreloading.com/primers.html

https://arxiv.org/pdf/1203.2701.pdf

http://castingstuff.com/primer_testing_reference.htm

https://www.shootingtimes.com/editorial/ammunition_st_mamotaip_200909/100079

https://www.osti.gov/biblio/6244672

troy fairweather said:

Some good to know info on primers, some info maybe a little dated but most is still good.

Sorry not linking to the proper page, working on finding it.

Click to expand...

Here you go - http://www.jamescalhoon.com/primers_and_pressure.php


More primer related articles from Rifleman's Journal - https://web.archive.org/web/2015030...ansjournal.blogspot.com/p/articles-index.html

Primers - Small Rifle Primer Study
Primers - Large Rifle Primer Study
Primers: Wolf .223 Primer Flash Test
Primers: Lead-Free Primer Evaluation
Primers: Large vs. Small Flash Hole Test
Primers: Seating Pressure and Pre-Compression
Primers: Misfires
Primers: It Don't Go Bang

A couple of comments on the James Calhoun article:

1. The mechanism for producing "pierced" primers is interesting. The cartridges in this photo are arranged in order of increasing powder charge, from left to right. As charge increases, a point is reached where the primer dent practically flattens itself back out. With a little more powder, the dent inverts, creating a nipple where the dent should be. The nipple then cracks around the base and breaks off, leaving a nice circular hole and a small bit of primer free to jam up the rifle mechanism. A thicker primer cup is the usual remedy.



2. The articles assertion that you can estimate pressure from case head expansion is no longer well accepted. Here is a graph from an article I did a few years ago, which pretty much destroys the CHE myth. The vertical axis is the pressure measured by strain gauge, and the horizontal axis is the case head expansion.



For the statistically curious, CHE explains less than 1/4 of the variation in actual peak pressure. There is a little information in CHE, but it is mostly just random statistical noise. You have to average about 140 case heads (random noise averages down as sample size increases) to get precision equivalent to the CUP system, which in turn is not as precise as either piezo or strain gauge measurements.