Small Rifle Primer Strength

[Keith Hansley in NC]

I would like to know where I would be able to find data on the strength, how hot ?) of small rifle primers. Specifically: WSR,Fed 205, Fed 205M, CCI BR-4.
All info or where to find is greatly appreciated.

Keith in NC

 

[tiny68]

I don't think there is such a thing. Too much variables. It varies with powder, case capacity, probably even the brass. Maybe someone will have a different opinion, but I always drop a little in charge when trying a new primer and start working back up. tiny

 

[Steve Blair]

Primer brisance is the metric you need. Following are some links; unfortunately, none are authoritative. YMMV

http://www.castingstuff.com/primer_testing_reference.htm
http://www.reloadingroom.com/index_files/Burn%20Rates.htm

I also attached a decent article by John Barsness in Guns Magazine. It explains some basic concepts and provides reference for correct terminology. Primers vary considerably from one manufacturer to another and slightly from lot to lot of the same manufacturer. The correct choice will make a large difference in the results.

Generally, Winchester primers, created to ignite ball powders, are a little hotter than other brands, Remington the lowest. Again, YMMV. Always test, never start with maximum loads and only vary one parameter at a time.,i.e.: don't change the powder charge and primer simultaneously and expect valid results).

 

[cliffy]

CCI 400 primers are designed for .22 Hornet, .218 Bee, .219 Zipper, and .222 Remington loads: NOT for .223 Remington! At .020' thick cup metal, these primers are minimal, at best, for light .223 Remington loads. They can cause primer piercing within stout loads in .223 Remington applications. CCI 250 Magnum primers are .025' thick and actually designed for .222 Remington Magnum and .223 Remington loads. Pierced primers are no joke as they crud-up bolt interiors and trigger mechanisms. Cliffy

 

[Keith Hansley in NC]

Thanks to all for the info

Keith in NC

 

[tenring]

German Salazar wrote an article for Precision Shooting on primer strength,included photos) about 6-8 months ago. I don't have an index; perhaps someone else can cite the month it was published.

 

[GermanS1]

Small Primers: http://riflemansjournal.blogspot.com/2009/06/primers-small-rifle-primer-study.html

Large Primers: http://riflemansjournal.blogspot.com/2009/06/primers-large-rifle-primer-study.html

 

[Winchester69]

CCI 400 primers are designed for .22 Hornet, .218 Bee, .219 Zipper, and .222 Remington loads: NOT for .223 Remington!

Thought that was the Remington 6 1/2. Clarification?

 

[infantrytrophy]

CCI 400 primers are designed for .22 Hornet, .218 Bee, .219 Zipper, and .222 Remington loads: NOT for .223 Remington! At .020' thick cup metal, these primers are minimal, at best, for light .223 Remington loads. They can cause primer piercing ...
Cliffy

Cliffy,

Are you sure that this is correct? According to information on CCI's web site, their '400' small rifle primers are designed 'For most standard loads in cases requiring small rifle primers'.

I have used the CCI 400, CCI BR4 and Remington 7 1/2 primers in my .223 loads for service rifle competitions. They all performed well and careful inspection of the primers after firing showed no problems. I could not tell the difference in point of impact or accuracy among the different primers. My loads are 24.4 gr RL-15 with Sierra 69's and 24.0 gr RL-15 with Sierra 77's and 80's.

Do you have a source that documents the above limitations? If so, please post this. If this is true, I have some '400' SR primers that I will return to the retailer and buy the '450' or 'BR4' primers instead.

Thanks.

Randy Sikes

 

[jthyttin]

If there's no primer flow to firing pin hole, just use the CCI 400s. Only higher pressure loads need thicker primers.

Here's the link to primer cup thickness comparison. I posted it also to other thread on the subject. I bookmarked it a year or two ago when the subject was discussed on this forum.

http://www.jamescalhoon.com/primers_and_pressure.php

 

[cliffy]

As I generally load to MAXIMUM in .223 Remington, my rifle's firing pin has pierced many CCI 400 primers, whilst I find this a non-problem while utilizing CCI 450 primers, although I've yet to have a pierced CCI BR-4 primer. Strange . . . 400, since they work great in .454 Casull applications to the Max. Cliffy

 

[JERRYHM]

German,

I see that you were getting 3.5 inches of vertical using the cci br4s at 600 yards and the other primers were under that. I guess I should use the fed 205m for 600 yards as my cci br4s were only getting about 1.000" of vertical at 600 yards. My tube gun dasher (bench rest).

Have you tried the small primer in the 308 cases? I found no difference between br4, 205m and rem 7 1/2 both in ES and in 1000 yard groups using the small primers in the larger cases.
Jerry

 

[GermanS1]

Jerry, my figures are from prone shooting with irons, so the comparisons to bench/scope won't be too exact, but I think the relationships will hold up.

I have shot a lot of the small primer .308 cases and have not found any real improvement over the best of the large rifle primers. Bob Jensen still swears by them, but that just hasn't been my experience.

Bob and I do a lot of testing together on his Oehler 43 system, but he's in the process of getting a new laptop to drive it and we've been unable to test for a few months. I have a beautiful test of weighed primers waiting to go; hopefully we'll get it done this winter.

 

[fdshuster]

My "standard" primer for AR-15 service rifle and NRA Hi Power match loads (Compass Lake built uppers) is the CCI400, and buy them by the carton of 5K. Standard match load is 25.5 of Varget with the 69 gr. Sierra #1380, and after many thousands of rounds fired, have never had a pierced primer.

 

[Rust]

There are other factors beyond just primer cup thickness which can contribute to the phenomenon we tend to refer to as primer piercing. Piercing would imply that the firing pin actually fully penetrated the primer cup material on stricking the primer. A more accurate description would be that the pressure of the fired round punches out the section of primer struck by the firing pin.

In my experience there are several things which can contribute to the process of primer piercing beyond simply pressure and primer cup thickness.

When the primer is struck by the firing pin, it weakens the metal by deforming it. It will be weakest in the transition zone between the deformed metal and the rest of the primer. The pressure can then shear the deformed section of metal much like a punch press.

A sloppy firing pin fit can certainlly contribute to this, because it leaves a lot of space for the metal of the primer to flow into which allows more weakening of the primer metal. A typical indicator would be cratering of the primers even with mild loads.

Excessive firing pin protrusion can be another contributor, the deeper firing pin strike produces more weakening of the primer metal.

A less than perfect firing pin profile can contribute, an other than hemispheric or mild ellipsoid firing pin tip can allow for additional weakening of the primer cup material.

And everyone is pretty much familiar with the process of excessive headspace allowing the primer to excessively slam back and forth in the primer pocket.

I've even run across one bolt in which the firing pin hole was quite a bit off center. Pierced primers were not so much the problem as inconsistant ignition which showed up as very poor ES/SD numbers. Oddly enough the rifle was very accurate out to 300 yards, more accurate than I would have expected given the large velocity spreads.

While a thicker primer cup may solve the problem, addressing any other contributing factors which potentially exist is always a good idea. I recollect going through several firing pins for one 700 before I finally got a good one, and finally having to replace the entire bolt and carrier assembly of an AR to solve its occasional hiccups.

 

[RDavies]

With regard to German getting more verticle with one type of primer, I would look too much into that for another reason. A different primer might either move the velocity up or down, just out of the accuraccy node. Adding or removing .2gn or so of powder might be all it needs to make it even better than the other powders. The velocity spread with each type of primer/powder combination is relevant though.

 

[GermanS1]

CR500, I agree completely with your analysis. My main objective with the tests were to see what, if any corelation existed between flsh size and pressure. Then I carried it forward into MV and the SD of MV and the SD of pressure. The firing tests at 600 yards were not too important to the testing and are subject to too many variables to be taken as definitive in any way.

 

[cliffy]

This site explained to me why I was piecing Remington 6 1/2 and CCI 400 primers, which both have similiar specs. Cliffy

http://www.jamescalhoon.com/primers_and_pressure.php

 

[flatlander]

Anyone who's experienced pierced primers in any rifle for any reason should be checking the tip of the rifle's firing pin with optical magnification. It only takes one pierced primer to start eroding the tip of the pin - in some cases, that's all it takes to cause enough roughness to cause piercing with ANY primer afterwards. Most AR shooters are aware of this, and since it's so easy to remove an AR15 or AR10 firing pin, there's no excuse not to take a good look at one after you've experienced a pierced primer.

Like several others here in this thread have mentioned, I've used CCI 400s in some pretty warm 223 loads with no problems whatsoever.

 

[cliffy]

I've switched firing pins in my Ruger Model 77 Mark II .223 Sporter to a Tubb Speedlock firing pin and spring. Still, I will only use CCI 450 and MAGTECH 7 1/2 Magnum primers in my hot .223 loads for best results. 3965 fps from a RL-10x powder charge with a 36 grain Barnes Varmint Grenade is as hot I will go. These are my "Lightning Bug" loads, chronographed at 75 degrees Fahrenheit. Cliffy