PRIMER HARDNESS

[Webster]

Guys mention some primer cups being harder than others. Is it really hardness or thickness? Has anyone actually measured the hardness of different brands and types? If I wasn't retired I could do it.

Just looked up some old post. They mention that the cups are usually made from cartridge brass. The manufacturers specify the hardness they want in the sheet brass they buy. The hardness is determined by the amount of cold rolling of the sheet metal.

 

[jk80]

If you check the search function there's a chart for primer specs.

 

[Larryh128]

Usually std primers are .020 and mags .025 . Hardness??? With that said the hardest primers I have used are CCI #34. All I will use in an AR-10. Work equally well in bolt guns, I have swapped CCI 250 & #34 with the same load and I can't tell the difference on paper.

 

[Webster]

If you check the search function there's a chart for primer specs.

The charts don't give actual hardness numbers. Rockwell or Vickers values from a hardness instrument.

 

[varget204]

CCI' shave had a 40 + year history of being harder to ignite,especially CCI 209's. in centerfire 5- 204 Rugers, 6 Creedmore, 6.5/284. & 2 6 BRA's have had more CCI 400,450, & BR not fire than all other primer brands combined. Most tried to fire 2-4 times large dents in primer cup,most of the CCI's ,a few Rem 7 1/2, 7 a Few Winchesters, Federal Match primers, in 50 years of shooting.most of the centerfire primers have been in last 10 years. deprimed,placed on a anvil & Smacked with a Hammer [ Scientifically lol ] All have gone Off. Believe it is the Primer anvil Depth Placement ??

 

[Oso]

As memory serves, James Calhoun, as in designer of 19 Badger, had a paper on primer cup thickness. You might go check his website to see if it is still listed.

 

[RegionRat]

Even if you had the cup harness and thickness values, would that information make you happy?

Isn't what you really want to know called the lower activation energy?

In a ballistics lab, there is more than one way to test a primer's activation energy, but one of the common ones uses a drop weight where drop height correlates to activation energy.

For mil-spec primers, there is a lower height at which primers shall not activate, and then another one at which 100% shall activate. This concept is to prevent accidental ignition and to guard against slam fires.

So, those two heights are important. One represents the safety against accidents, and the other represents making sure they go off when required.

Some commercial primers do not conform to the guards against slam fires, which is why there are mil-spec primers and also some commercial ones rated for semi-autos. On the other hand, some commercial primers are not recommended in semi-autos for the same reasons.

Ammunition companies do not publish their engineering in the public domain. If you ask them about their primers in terms of being recommended for semi-auto or not, they will tell you. YMMV

 

[46and2]

Even if you had the cup harness and thickness values, would that information make you happy?

Isn't what you really want to know called the lower activation energy?

In a ballistics lab, there is more than one way to test a primer's activation energy, but one of the common ones uses a drop weight where drop height correlates to activation energy.

For mil-spec primers, there is a lower height at which primers shall not activate, and then another one at which 100% shall activate. This concept is to prevent accidental ignition and to guard against slam fires.

So, those two heights are important. One represents the safety against accidents, and the other represents making sure they go off when required.

Some commercial primers do not conform to the guards against slam fires, which is why there are mil-spec primers and also some commercial ones rated for semi-autos. On the other hand, some commercial primers are not recommended in semi-autos for the same reasons.

Ammunition companies do not publish their engineering in the public domain. If you ask them about their primers in terms of being recommended for semi-auto or not, they will tell you. YMMV

Unis Ginex provides this information.
Othe primer manufacturers should give it too, I just didn't know where to look.

 

[RustyInBend]

Is thicker better, or harder better? Seems a forum full of old retired shooters is a terrible place to ask that question.

 

[Doom]

Is thicker better, or harder better? Seems a forum full of old retired shooters is a terrible place to ask that question.

it doesn't matter as the combination of both properties ultimately determine the sensitivity and pressure retaining capability. The difference is thickness occupies internal volume that is limited by external dimensions and hardness increase strength without occupying volume.

 

[Webster]

Is thicker better, or harder better? Seems a forum full of old retired shooters is a terrible place to ask that question.

Shoot them then you know everything you need to know. I'm retired but still an active target shooter and varmint hunter. You don't need to dump on retired guys. Everyone on this website is trying to provide info. and help others. Sometimes it's helpful sometimes it's not.

No-one complains about getting 50 replies on this is how I lube my cases or fifty replies to a simple question or responses that have nothing to do with the original question.