Primer Hardness

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BlackDog22

Inactive
It is interesting that there is no data available that I can find that tests the hardness of primers based on Brand - Usage - Wall thickness - Hardness (indent distance to standard dimension firing pin.)

I bought a Tanfoglio 9mm a while back that I bought near new. The guy obviously sold it because it was misfiring every 8th round. (And just forgot to mention that to me when he sold it :-P )

I took it to the importer and he gave me a few "guaranteed" fixes that didn't do a thing to stop the issue. One acquaintance told me to try different types of ammo until you get one that works. Well he was right, but what he probably didn't know and neither did I at the time, was that primers come in different harnesses.

Although the wall thickness of the primer may be the same, the hardness of the primer can be quite different. I learned through expensive experience that CCI primers are hard and Federal Match Primers and nice and soft.

My "Cow" of a 9mm Now works 99.99999% of the time running on Federal Primers.

I think the importer is still telling people to swap firing pins, and shaving off firing pin blocks and sand papering this and that. What a laugh.

Well I was delighted with the fix. I don't understand why there is no "hardness" grading for each make and model/brand of primer on the market. It would certainly have made my finding a fix easier.

Reading the opinions hear about which primer is soft or hard is a prime reason why someone should do the testing. Because some of the comments are just plain wrong!!

So the Rule is "LIGHT PRIMER STRIKES - TRY A DIFFERENT BRAND OF PRIMER" They aren't all the same!!!
 
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Early in the small primer pocket 45 brass days, I used some Rem 6 1/2 primers in them, and found them to be more consistent than the spp primers I compared them to.
 
OP is older than dirt.
Primer/primer pocket dimensions are here.
The differences in magnum vs regular is the priming compound and nothing else. Magnum primers burn a bit hotter for a bit longer. Cups are the same.
http://ballistictools.com/articles/primer-pocket-depth-and-diameter.php
Oh and those CCI so-called "Milspec" primers are magnum primers and nothing more. They're absolutely unnecessary for use in any battle rifle. Brilliant marketing campaign though.
 
BlackDog22,

Welcome to the forum.

Since this thread is 7 years old, you will get more responses and be addressing fewer no-longer-participating members if you start a new thread (button in the upper left part of a forum window listing the threads) than by revivifying an old thread (commonly called a Zombie Thread when brought back). I will make the new posts into a new thread for you.

What you are referring to as "hardness" is, I infer, not mechanical hardness but how easily a primer ignites. That difference is affected not only by mechanical thickness and hardness of the cup, but by the sensitivity of the priming mix used and the rigidity of the anvil that supports the priming pellet against indentation of the bottom of the cup. Regardless of Mr. O'Heir's persistent misinformation on this point, the military hardness primers are less sensitive than their commercial counterparts and they are not all magnum. The Federal GM205MAR primer, for example, is the same as their 210M primer, a standard power level match primer, except it has a thicker cup to reduce its sensitivty to match the military H-test standard you see below. The CCI military spec primers have the same priming mix and cups as their magnum primers, but have anvils with shorter, more widely spread legs to reduce their sensitivity from that of the standard magnum primer to that of a military primer. This is done to reduce the chance of a slamfire occurring when a military bolt with floating firing pin chambers a round, and event during which the firing pin often makes a "light" impact with the primer as the bolt closes. If that light impact sets off the primer, you have what is called a slamfire (firing as the bolt slams closed). These are not common events, but based on the number of slamfires I've been present for at matches, I've estimated you see one about every 15,000 rounds or so. Usually, this occurrence is due to a high primer not properly seated by a handloader, but I've witnessed one with Lake City ammunition and board member Slamfire had two Garand rifles destroyed by slamfires happening before the bolt was fully closed (aka, an Out Of Battery firing, or OOB firing), an even rarer occurrence. Both of his were with Federal primers of the non-magnum non-military sensitivity type.

The method for determining sensitivity is the H-test (height test) which puts controlled amounts of kinetic energy into a standard firing pin to see how much is needed to cause ignition to occur reliably and how little is needed to cause ignition. A primed case is placed in what amounts to an inverted shell holder with the firing pin with an average protrusion stop making contact through the center of it. For small rifle primers, an abbreviated test is to use a 1-29/32 steel ball¹ weighing 16.34±0.02 ounces dropped onto the firing pin from a height of 1.5 inches onto 150 sample primers from a lot being qualified without any of them firing. Then a sample of 300 more primers from the same lot are subjected to dropping the same ball from 9" without more than 5 misfires occurring. The commercial primers called "military sensitivity spec" primers, meet that military requirement or its equivalent for large rifle primers.

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¹ Note that this is typo'd as a 1-19/32" steel ball in MIL-46296C, but a steel ball at that smaller diameter would weigh less than 10 ounces, where 1-29/32" diameter chromium steel ball bearing with density of 7.79 g/cc would hit the weight exactly.
 
Mehavey,

I took his post and the answers out of the zombie thread and created this new thread with them (see the last sentence of my paragraph on it).
 
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