Primer Tests

[dale2242]

Here is a challenge for you engineers and machinists. We constantly hear about the hardness of primer cups, sensitivity of different primers, and so on. Why don`t you build a couple of testing devices to clear up some of this controversy.

1. A device to gauge the pressure it takes to seat a primer. The primers would all have to be seated in the same primer pocket to make it accurate. This would tell us the size [ larger or smaller] each brand of primer is and how good the quality control is in relation to size.

2. A device to measure the impact it takes to detonate a primer, thus showing the sensitivity of each brand and are the cups of pistol primers really softer than rifle primers.


There are many clever and capable people in this forum, lets see what you can come up with. Some may tell me this has been done. If so,please show me the results....dale

[felix]

Will only work if you have a primer lot that is like the tester's. Therefore, let's wait for about 5 years and let the current manufacturing runs settle down. ... felix

[Green Frog]

Here is a challenge for you engineers and machinists. We constantly hear about the hardness of primer cups, sensitivity of different primers, and so on. Why don`t you build a couple of testing devices to clear up some of this controversy...

There are many clever and capable people in this forum, lets see what you can come up with. Some may tell me this has been done. If so,please show me the results....dale

"Been there, done that." Not me, actually, but I was peripherally involved, along with Dale53, in the testing of the sort you describe done by the late Charlie Dell in the late '90s. He had a pendulum style device with a protractor to show how much impact (relative) was required to dependably set off the various primers being tested, and did photos of the flash pattern as well as having the primer drive a lead pellet to measure strength of the primer effect. I don't remember whether he ever published his results in their entirety, but whatever he did publish would have been in the Single Shot Rifle Journal about the year 2001, IIRC. You might inquire over at

http://www.assra.com

as to whether the archives they maintain have those data. Also, his book, co-authored with Wayne Schwartz, probably had some information about the first of the primer research he did, but since all of this was near the end of his life and his health was failing, not everything he did got published. :cry:

Froggie

[Rocky Raab]

I did a brissance test many years ago, to establish a "burn rate" table for primers. It was a major undertaking even then to locate samples of every type of primer available. These days, it would be impossible, I think.

Not only that, but it took a LOT of primers and I wouldn't want to "waste" them today even if I had a large supply of them. The test proposed would require thousands of primers.

[AZ-Stew]

I do CAD mechanical design for a living and could easily come up with a device to test seating force using a load cell and a couple of machined parts, but as someone else said, primer lots change and after a number of seatings, the case used as the primer pocket test vehicle would have to be changed as well, due to wear, with no guarantee that the diameter, depth or hardness of the brass would be equal to the previous cartridge.

Regards,

Stew

[shooter93]

Get hold of Charlie Dell's book, he did all kinds of very good research on primers etc.