Primer sensitivity

They are more sensitive to point of impact and the anvil in the primer is designed so when the firing pin make and indentation it impacts the priming compound between the primer cup and the anvil. That is how they are designed to work.
A tennis ball won't do anything to them. A baseball would set one off if you threw it at it and it hit just right.
A hammer will set it off immediately. What doesn't seem to set them off is a slow deliberate crush. I've crushed a few in the last 48 years I've been reloading.
I have mangled primers beyond recognition and they didn't go off. And it was because I didn't hit it with a crushing blow.

As far as whether some primers are more sensitive than others, yes, but not because of the primer compound, but more because of the thickness and or hardness of the cup.

Any magnum primer has a thicker cup than a non magnum primer respectfully, whether pistol or rifle. Again cup thickness and hardness.
A normal small pistol primer should not be used in a full pressure small rifle cartridge, even though they are the same size and fit, because the firing pin would probably pierce the primer on firing and damage to the bolt face of the rifle.
However a small pistol magnum primer could be used in a low pressure rifle load and probably survive fine, say up to about 40,000lb. Above that you would need the thicker cupped rifle primer that would handle the higher pressure.

At the end of the article below there is a little information on pistol primer sensitivity.

https://www.shootingtimes.com/editorial/spring-rates-and-trigger-pull-weights/383919

I understand that millennial primers are very sensitive, and often require a "safe space" and gun-free zones, or they can get their feelings hurt.

Although the compound in primers is extremely sensitive, to be set off by striking they almost need to be installed. Seating the primer into the primer pocket is what places the anvil in close enough proximity that a firing pin can set them off. So simply dropping a dozen on the floor is not nearly the issue hitting one with a hammer is going to be.

TightgroupTiger covered it pretty well. Will add Mil spec primers for AR's have a different anvil to make it less sensitive. This is due to the floating FP being used

Sometimes, in our youth we do silly things like shooting 209 shotgun primers with bb guns. They ate hard to hit at 20 or so feet, but you know when you hit one. I never tried to set any primers off using hammers or Amy other means.

I've used them on our "glorious fourth" celebration. A hammer works wonderfully. JM

tightgroup tiger said:

They are more sensitive to point of impact and the anvil in the primer is designed so when the firing pin make and indentation it impacts the priming compound between the primer cup and the anvil. That is how they are designed to work.
A tennis ball won't do anything to them. A baseball would set one off if you threw it at it and it hit just right.
A hammer will set it off immediately. What doesn't seem to set them off is a slow deliberate crush. I've crushed a few in the last 48 years I've been reloading.
I have mangled primers beyond recognition and they didn't go off. And it was because I didn't hit it with a crushing blow.

As far as whether some primers are more sensitive than others, yes, but not because of the primer compound, but more because of the thickness and or hardness of the cup.

Any magnum primer has a thicker cup than a non magnum primer respectfully, whether pistol or rifle. Again cup thickness and hardness.
A normal small pistol primer should not be used in a full pressure small rifle cartridge, even though they are the same size and fit, because the firing pin would probably pierce the primer on firing and damage to the bolt face of the rifle.
However a small pistol magnum primer could be used in a low pressure rifle load and probably survive fine, say up to about 40,000lb. Above that you would need the thicker cupped rifle primer that would handle the higher pressure.

Click to expand...

Hey, I learned something! Thanks for that, now that leads to a related question; Would there be an issue or potential problem using small rifle primers, Magnum or Standard, in a small pistol cartridge, Magnum or Standard (say, .38 SPCL / .357 Mag)? Reason I ask...I've "inherited" a sandwich bag of small primers. I know their not "old" and probably just got dumped out of pre-loaded primer tubes when the previous owner sold off the loading presses. I hate to toss a small primer in the trash, especially given their respective rarity today and there's probably 300 - 500 of them in the bag. What recommendations would you make as far as loading them in .38 SPCL and .357 Mag cartridges?

Small primers in general have more cautions.

https://www.thehighroad.org/index.php?threads/remington-primers.875144/#post-11644325

https://www.thehighroad.org/index.p...mponent-crunch-try-this.874696/#post-11637233

Lee Precision disallows using any Federal brand primers except one at a time and has other quantity limits on Winchester primers in much of their equipment due to greater sensitivity to sympathetic detonation of these brands and types of primers.

https://support.leeprecision.net/en/knowledgebase/article/primer-brand-restriction

I've read Lee's test apparatus was a chamber with one of heir products having a certain number of primers in the feed tray, one primer above the punch ready for the handle to be squeezed, and a primed cartridge case in the shell holder to represent an incipient double primer feed. A lit propane torch was aimed at the cartridge neck providing delay, eventually the primer already seated in the cartridge case went off due to eat, not mechanical pressure, but it definitely went off. Lee's limits were then established by the degree of sympathetic detonation that occurred.

Packaging for current manufactured Federal brand primers provides greater spacing between primers in the package than CCI, Remington, and Winchester due to such sensitivity.

Some older Remington and CCI primer packaging only had material between rows of primers with primers on their side edges, with the side edges touching within each row.

I find that you really have to work hard to set one off. Over the years I have dropped dozens on the cement floor and mangled more than a thousand trying to seat them. So far none of mine have gone off on me. There are pictutes of primer tubes exploding and reports of popped primers so caution is warrented but avoiding a sharp blow seems the best answer.

23tony said:

Can you hit it with a tennis ball without it going off? A basketball? A hammer?

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Tennis Ball? Probably, but not definitely.
Same with a basketball - only I'd bet with higher probability.

Hammer? 99.99999% probability YES, it will pop.

How about a 12 ga shotgun shell?
With 1 of these on the primer?
And paper streamers for a tail.
Gosh we were DUMB!!!!
Its a surprize I made it to 60 years old

Farmer Dave said:

Would there be an issue or potential problem using small rifle primers, Magnum or Standard, in a small pistol cartridge, Magnum or Standard (say, .38 SPCL / .357 Mag)?

Click to expand...

I was just today loading 9mm with small rifle primers. I have loaded some with small pistol magnum primers.
I have not had a failure to fire in a hammer fired gun, I can't say about striker fired pistols.
Velocities of the one specific load I checked did not vary AT ALL with 6 of 7 brands and types tried. Strangely, Remington small pistol gave a bit higher speed than any other, magnum and rifle included. Could pressures have varied without changing velocity? Maybe, but I am not loading to the maximum so I am not concerned with it.

Before Federal made magnum pistol primers, they recommended their small rifle primer for .357 magnum.

Farmer Dave said:

Hey, I learned something! Thanks for that, now that leads to a related question; Would there be an issue or potential problem using small rifle primers, Magnum or Standard, in a small pistol cartridge, Magnum or Standard (say, .38 SPCL / .357 Mag)? Reason I ask...I've "inherited" a sandwich bag of small primers. I know their not "old" and probably just got dumped out of pre-loaded primer tubes when the previous owner sold off the loading presses. I hate to toss a small primer in the trash, especially given their respective rarity today and there's probably 300 - 500 of them in the bag. What recommendations would you make as far as loading them in .38 SPCL and .357 Mag cartridges?

Click to expand...

With the small rifle or the magnum pistol you will want to reduce your load about .2-.3 of a grain of powder because they may or could have more priming compound in small pistol magnum primers and small rifle primers, than they do in small pistol primers. I think CCI is a perfect example of this.

Using small rifle primers in pistol cartridges may cause a problem if the hammer of your revolver isn't strong enough to set them off due to the thicker cup.

I have a SP101 chambered for .327 Federal Magnum and Federal recommended that when re-loading this caliber, we use a small rifle primer so we didn't have pierced primers from the excess pressure.
The .327FM runs at around 45K of pressure and is a stout little cartridge,

I never had one of the Federal .327FMs with small rifle primers not go off. At the same time, I reload these to max load and I have never pierced a small pistol primer in it either.
But I know my gun smith addressed the fire pin in this SP101 when I had it in for a spring kit, which was right after I bought it.

Never set off a primer unintentionally in 43 years of reloading.

A friend did set one off unintentionally, but he was trying to cut the head off a loaded case stuck in a seating die using a hacksaw. Don't do anything like that and you have nothing to worry about.

Hondo 60 said:

Hammer? 99.99999% probability YES, it will pop.

Click to expand...

Ever tried?

I have. They rarely detonate. Hammer on a flat steel surface will occasionally set one off, but less than 20% in my small sample size.

23tony said:

Also related, I'm wondering how tightly packed the powder is in a shell? I simply haven't had a chance to do anything given the limitation on primers, so no chance to try it for myself yet...

Click to expand...

Some loads will have compressed powders. As long as you follow published load data it produces no problems, and even has some advantages.

23tony said:

I'm wondering how tightly packed the powder is in a shell?

Click to expand...

Varies greatly.
Old Calibers like 45 Colt, 38 Special are fairly loosely packed, depending on what powder is used.
As fxvr5 alluded to some more recent rifle loads will be compressed.

fxvr5 said:

As long as you follow published load data it produces no problems, and even has some advantages.

Click to expand...

As fxvr5 said ^^^^^^^

23tony said:

Still being curious: last night I measured out 1/10 ounce of pepper (powder is still unopened until I find primers), which tha interwebz tells me is about 44 grains. That worked out to about one teaspoon. Unless I was reading the wrong page, my Lyman's book indicates in the 15-ish range for .357 loads. If pepper is anything close to powder in weight, 1/3 teaspoon seems like it wouldn't fill the casing very much at all.

Yes I know apples/oranges/pepper/powder. Maybe I should just open some up and see for myself.

Click to expand...

Will you be using pepper as your propellant?

23tony said:

Yes I know apples/oranges/pepper/powder. Maybe I should just open some up and see for myself.

Click to expand...

I’ve made pepper poppers before... but it’s a bit different.
You should look up “density”. Different powders have different density, including different peppers. Good luck!

Mr. Zorg said:

Packaging for current manufactured Federal brand primers provides greater spacing between primers in the package than CCI, Remington, and Winchester due to such sensitivity. Some older Remington and CCI primer packaging only had material between rows of primers with primers on their side edges, with the side edges touching within each row.

Click to expand...

I disagree. Packaging was changed to comply with shipping, and proposed future shipping regulation. I have no information about the Federal primers but CCI told me that their primers have remained the same all through the years, but in order to ship them, they needed individualized compartments. Even so, its hazmat. In the "old days", and I go back 45 years or so on reloading, you'd get primers in a smaller tray, each one touching the other in little rows, shoulder to shoulder (in figurative terms). Did anyone ever hear of primers failing in shipping? Not once ever. The Lee manual states that "primers are more sensitive today" and goes on to use the packaging as proof. I think they're connecting dots that need not be connected. Everyone's primer feeds that hold multiple primers has evolved, lawyer'd up. I suppose they are safer, but perhaps a cure waiting for a disease. Reoading well over 10 million rounds over the mid 80's to mid 90's, we never had one accident, and neither was there one prior to my service at that range... going back to the mid 1960's when it opened. Our primers were standard consumer packaging, and we dumped them into a vibratory bowl to get 'em lined up, right way up, and tubed. They got no real special treatment other than the bowl being higher than people. I think the top was about 7 feet from the floor - but I didn't measure it. I couldn't see into it, and I was just shy of 6'2" then... jeeze shrank a half inch in old age!

On one occasion, we had a brazen, opinionated, and very vocal "ex NYC cop" (as he was proud to tell everyone), pull his Glock out of a range bag, after a shooting session - at the cash register (a BIG no-no), take a loaded magazine and insert it (another BIG issue and he was getting warned at that point), drp the slide the pull the trigger, sending a 9mm bullet down the counter, across a small aisle, and into a display of ammo in a shelf against the wall. One round went off in the box of ammo. Mr. "ex NYC cop" got his ass chewed, his membership revoked/refunded and his sorry carcass ejected.

The only accident I've ever heard of with primers was a well known gunsmith decapping live military brass, catching the unfired primers in a large container on the floor under his press. This is an especially dangerous practice, as the decapping pin is pressing on the back of the anvil, and if that by itself doesn't act like a reverse firing pin, then the anvil setback in the cup has made things subject to less movement for an firing to happen. He had the entire large open container of unfired primers go off (aka explode) when one of the cases "went bang" as the decapper hit the anvil in a case, sendind debris down the tube that dropped into the container. It was said he died instantly. To this day I am scared silly about decapping a live primer, and take extra-extra precaution against accidents. For me its usually just one or two cases that were mistakes, but still... one goes off you got little bits flying all around the place, maybe into an eye, an artery... you get the idea.

Project355 said:

I disagree. Packaging was changed to comply with shipping, and proposed future shipping regulation. I have no information about the Federal primers but CCI told me that their primers have remained the same all through the years, but in order to ship them, they needed individualized compartments. Even so, its hazmat. In the "old days", and I go back 45 years or so on reloading, you'd get primers in a smaller tray, each one touching the other in little rows, shoulder to shoulder (in figurative terms). Did anyone ever hear of primers failing in shipping? Not once ever. The Lee manual states that "primers are more sensitive today" and goes on to use the packaging as proof. I think they're connecting dots that need not be connected. Everyone's primer feeds that hold multiple primers has evolved, lawyer'd up. I suppose they are safer, but perhaps a cure waiting for a disease. Reoading well over 10 million rounds over the mid 80's to mid 90's, we never had one accident, and neither was there one prior to my service at that range... going back to the mid 1960's when it opened. Our primers were standard consumer packaging, and we dumped them into a vibratory bowl to get 'em lined up, right way up, and tubed. They got no real special treatment other than the bowl being higher than people. I think the top was about 7 feet from the floor - but I didn't measure it. I couldn't see into it, and I was just shy of 6'2" then... jeeze shrank a half inch in old age!

On one occasion, we had a brazen, opinionated, and very vocal "ex NYC cop" (as he was proud to tell everyone), pull his Glock out of a range bag, after a shooting session - at the cash register (a BIG no-no), take a loaded magazine and insert it (another BIG issue and he was getting warned at that point), drp the slide the pull the trigger, sending a 9mm bullet down the counter, across a small aisle, and into a display of ammo in a shelf against the wall. One round went off in the box of ammo. Mr. "ex NYC cop" got his ass chewed, his membership revoked/refunded and his sorry carcass ejected.

The only accident I've ever heard of with primers was a well known gunsmith decapping live military brass, catching the unfired primers in a large container on the floor under his press. This is an especially dangerous practice, as the decapping pin is pressing on the back of the anvil, and if that by itself doesn't act like a reverse firing pin, then the anvil setback in the cup has made things subject to less movement for an firing to happen. He had the entire large open container of unfired primers go off (aka explode) when one of the cases "went bang" as the decapper hit the anvil in a case, sendind debris down the tube that dropped into the container. It was said he died instantly. To this day I am scared silly about decapping a live primer, and take extra-extra precaution against accidents. For me its usually just one or two cases that were mistakes, but still... one goes off you got little bits flying all around the place, maybe into an eye, an artery... you get the idea.

Click to expand...

Well you may want to not only use Google, but information posted by others on this site WRT primer mishaps that resulted in injuries, and near miss incidents, as there's plenty such info available. You may perceive your anecdotal experience and what you've heard as all there is to it, but it's not difficult to demonstrate your anecdotal experience and information base is far from all encompassing.

Static electricity is a common root cause initiator in many such accidents, others include dropping a tube full of primers on a hard surface, to being just aggressive enough with a malfunctioning tube with stuck primers, to trying to forcefully insert a primer in a case that had crimping of the primer pocket that hadn't been addressed, to double feeding, and the list goes n and on as you'll see if you choose to seek out such information


Here, I'll post up a link to get you started along a path I personally found highly educational to me as a new reloader. This item is found in this very subforum, in the thread titled "Reloading Library of Wisdom" as it contains not only substantial factual knowledge but sage guidance from those who have "been there, done that". .

https://www.thehighroad.org/index.p...fortunate-events-warning-graphic-very.776339/

I've read the Lee primer sensitivity apparatus consisted of a strong box. Inside that box was a Lee Auto Prime with the tray loaded with whatever the number of primers were to be tested along with an appropriate shell holder plus a case that had already had a primer seated. This left a primer ready to raise up slightly below the primer already seated in the case, as if an imminent double feed event. A lit propane torch was also present with the flame aimed at the case mouth / neck area. This allowed a degree of time delay and at some point the primer already seated in the case would go off.

The results of all this testing was the basis of the number of primers Lee advised as a maximum to be loaded in the Auto Prime (and / or Auto Prime II) in the safety warning Lee included with the instruction sheet for those items. Initially only CCI &.Winchester primers were approved by Lee in those items, up to 100 total, as can be seen here.

https://www.google.com/url?sa=t&sou...FjAEegQIDhAB&usg=AOvVaw0IkWLE-1dvkn0Pt3TBMSvG

Those instructions were changed at a later point to endorse all CCI and Remington primers but different limits on Winchester primers as can be seen here.

https://support.leeprecision.net/en/knowledgebase/article/primer-brand-restriction

Note that use of any Federal primers in either device are only endorsed loading one single primer at a time, no change, as seen here. The material I read about this testing was all Federal primers in this testing would undergo sympathetic detonation no matter how few were in the apparatus when the primer already seated in the case went off.

https://leeprecision.com/files/instruct/PP2165.pdf

All driven by the testing at Lee Precision with regard to primer sensitivity. Not guesswork, not based on what Richard Lee had heard, but reasoned empirical testing.

If you choose to further broaden your personal knowledge base in these matters, you may find it worthwhile to purchase this book and not only read, but digest, the information enclosed. I have for broadening my own knowledge base.

https://smile.amazon.com/gp/aw/d/B08BDXM96W?psc=1&ref=ppx_pop_mob_b_asin_title

But there are many, many incidents you can find at no incremental cost available if you ever choose to put effort in doing so. I have.

Can only go on my experience and conversation direct with CCI.... which started off w/.22lr questions.