Brisance (?) values for primers like burn rates for powders?

[Steven66]

I was wondering if there is a reference to what I will call "the strength or power of" (since I don't know whether that is brisance or something else) primers that would indicate which would increase pressure significantly? As an example, let's say a Hodgdon published load reference specifies CCI 550 small pistol magnum primers (SPM) and the local gun store is out of CCIs but has Winchester SPMs or Federal SPMs. Does a prudent reloader (someone who wants to keep at or below maximum pressures) wait until the CCIs are available, or substitute brands and then use the chronograph (velocity) to see if velocities are comparable?

Short version: Is there a chart for primers that goes "warmer to hotter" like there is for powders (slower to faster)?

[Outpost75]

Efficiency of primers is not determined by explosive force, but by HEAT.

The purpose of a primer is to IGNITE the powder charge, not detonate it sympathetically.

The most efficient primers for igniting "difficult to ignite" powders are the WInchester WLR which features an aluminum metallic fuel which scatters hot, incandescent particles through the powder charge.

An easy way to test this for yourself is to set a camera on a tripod in a totally dark room, place a primer on a hotplate, prop the camera shutter open and photograph the flash in the dark room when the primer goes off.

The difference between Winchester primers and any others is dramatic.

I was told by an engineer at Olin Defense that there is no technical difference between "standard" and "magnum" primers, that they are made on the same line, at the same time and the "magnum" primers are determined by sorting to separate the primers having pellet weight which exceeds an X-bar + 1 sigma limit. It's pure marketing and as one QA guy joked to me, "It gives the bean counters a way to charge more money to consumers for primers the government would reject."

Federal primers are also good.

The Federal 215 magnum primer is the only standard size rifle primer which inserted into a bushing in the .50 BMG case will ignite a full charge of powder.

[Char-Gar]

As I understand the term "brisance" it represents the speed/rate at which a primers releases it's full energy. I think of it describing not power, or heat, but speed. I would imagine that brisance would also have an effect on both power and heat, but you need to talk to somebody with more tech knowledge than I have. I am something of a dunce at such things.

Back in the day, the Remington 9.5 primer was touted for cast bullet loads because of it's low brisance. I understood that to mean the slow burn did a better ignition of lighter cast bullet charges. I don't think today's Remington 9.5 are still low brisance, but I have about 15K of the old ones put up.

[Green Frog]

I was marginally involved with Charlie Dell and Dale McGee when similar tests were conducted, only Charlie had a fixture to hold the various primers and strike them with a plunger to set them off. The resulting photographs were interesting... I ran across a couple of them just the other day. :cool:

Froggie

[AggieEE]

Back in the 80's somebody, I don't remember who right now, did a article for "Precision Shooting" where he tested primers. He only tested small rifle match primers as that's what most benchresters use. He had a very short barrel 2 - 4", I think, and photographed the flash against a lighted grid. He also had a piezo film to an oscilloscope to give a pressure trace. Then he fired them for accuracy. His conclusion was the primers that had the mildest flash and pressure gave the best groups. He was shooting a 6mm PPC so it wasn't like it was a lot of powder but still. I don't remember what powder he was using but it was a proven accuracy load for his rifle.

[Larry Gibson]

Primer Brisance chart

Primers are not measured in "burn rate", but by their "Brisance".
Brisance - is a measure of the rapidity with which an explosive develops its maximum pressure

Here are the results of a test done to determine the brisance of primers. The testing was apparently done with a homemade ballistic pendulum, which left a lot to be desired. So, don’t take this as gospel but as a rough indicator. It does show there are great differences in primers


RIfle Primers
Brand/type_________Power Average___Range____Std. Dev
1... Fed Match GM215M___6.12______ 5.23-6.8_____.351
2... Federal 215 LRM _____5.69______ 5.2-6.5 _____.4437
3... CCI 250 LRM_________5.66______ 4.5-7.4_____ .4832
4... Winchester WLRM____ 5.45______ 5.1-6.0 _____.2046
5... Remington 9 1/2M LR _ 5.09 _____ 3.5-6.75 ____.6641
6... Winchester WLR _____ 4.8 ______ 4.1-6.0 _____.4300
7... Remington 9 1/2 LR __ 4.75 _____ 3.7-6.25 ____.5679
8... Fed Match GM210M __ 4.64 _____4.0-5.6 ____ .3296
9... Federal 210 LR ______ 4.62_____ 3.7-5.5 ____.3997
10.. CCI BR2 ____________4.37_____ 4.0-5.0 ____ .2460
11.. CCI 200 LR __________4.28 ____ 3.8-4.8 ____ .3218
12.. KVB 7 LR Russian_____ 4.27 ____3.8-4.8 ____ .2213
13.. Rem 91/2 (30 yrs old)_ 4.16 ____ 3.8-4.8 ____.3427

Pistol Primers
14 Rem LP ___________4.47_______ 3.2-5.6 _______.5171
15 KVB 45 LP Russian __3.89 _______3.3-4.2 _______ .2232
16 CCI 300 LP________ 3.18_______ 2.7-3.5 _______ .2406
17 Federal 150 LP _____3.11 _______2.6-3.5 _______.2090
18 Fed Match GM150M_ 3.05 _______ 2.6-3.7 ______ .2299

[Steven66]

Thanks. If I substitute a higher brisance primer for a given load, and I get more velocity out of that load, would I be correct in thinking that pressure had increased?

[M-Tecs]

http://www.6mmbr.com/primerpix.html

[Larry Gibson]

Thanks. If I substitute a higher brisance primer for a given load, and I get more velocity out of that load, would I be correct in thinking that pressure had increased?

Yes, pressure will have increased.