How sensitive are Primers?


December 13, 2003, 06:53 PM
How easy is it to accidently set off a primer? Things such as accidently stepping on one on a concrete floor, dropping one, etc?

I've never reloaded and am thinking about getting into it.


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December 13, 2003, 07:46 PM
primers arent very sensite to stuff like that. THe only time I have set one off accidentally is in a vacumn. who knows if that was heat or static electricity or pressure. The anvil has to be hit normally which is very small.

Standing Wolf
December 13, 2003, 09:09 PM
I've stepped on primers a few times without setting them off.

December 14, 2003, 12:21 AM
The only primer fires I've had were when loading the primer in the primer pocket due to misalignment. And that has only been a couple of times.

Black Snowman
December 14, 2003, 12:25 AM
Several things have to happen to ignite a primer but it can be summed up as a rapid pinch. There are a couple safety features built into a primer to prevent one from going off accidentily.

There's an "anvil" in the primer. A little spring that fits in the cup. It sticks out slightly from the cups edge. When the primer is seated in the primer pocket this anvil is compressed and puts the compound under a slight load. The firing pin hits the center of the primer where the anvil is an the pinch causes enough friction to make the compound ignite.

I have crushed many primers by accident. Usually when I don't set my progressive up correctly. I've seen them mushed sideways, seated upside down, and just generally mangled. Only once did I ever (stupidly) generate enough force to set one off when I tried to seat a 2nd primer on top of an old spent primer (didn't notice the decapping pin had popped up indicating a problem). It resulted in my ears ringing for a few seconds and me tearing apart my press to make sure everything was OK. At which point I correctly set it up so it wouldn't happen again.

It's possible to set a primer off by stepping on it but it would have to be on a hard surface and stepped on with very hard shoes and quite rapidly. Unlikely but possible.

EDIT: It's important to mention that some primers are more sensative than others. I use CCI primers which are netoriously difficult to set off. The one time I had one go off was a Federal, which are netoriously easy to ignite. Now I only use CCI and Winchester and I only use the Winchesters for 10mm.

December 14, 2003, 07:50 AM
I have never accidentally set off a primer. I have primed cases with the tool on my Lee turrent press and with the Lee auto-prime tool. Primers can be dangerous. Handle them with care and you needn't be afraid of them.

December 14, 2003, 05:01 PM
What is a primer going off comparable to? A firecracker? I suppose it also depends on if it's a handgun primer, shotgun primer, magnum rifle primer, etc.?

By the way, my interest started by me getting a T/C Encore this weekend. The store said it takes 209 shotgun primers. I've heard of 209, 209A, 209M, but don't know the difference, yet. I'm also planning to get involved in handloading for rifles (.45-70, etc.) I guess the primer handling just had me a little concerned about accidently setting one off...

And Jeeper - I also read about someone that was vacuuming up some gunpowder aroung his workbench. He evidently also picked up a lost primer and it went off in the vacuum, detonating the gunpowder.

What's the best way to clean up gunpowder? I can see that reloading will really take a LOT of care and attention.


Peter M. Eick
December 15, 2003, 09:37 AM
I have set off 2 primers that I can remember. Both were back in the 70's with a lee hand loader kit. I got to energetic tapping the primers into the case. Both were QUITE loud since I was only about 2 feet from the explosion. They have a lot more power then you would think!

By relative measure It was more then a black cat firecracker they make today for sound.

Black Snowman
December 15, 2003, 10:52 AM
Cleaning up powder:
Ideally load over a smooth floor and use a broom and dustpan to clean up powder. One of the "push brooms" can work well too. Otherwise a canister vacuum, including the Dust Buster, is relatively safe as the powder won't go through the fan or motor but still riskier than the manual methods.

December 15, 2003, 05:16 PM
Just steeped hard on a Small Pistol Magnum Primer with Cowboy Boots and it went off right away!


Black Snowman
December 15, 2003, 05:55 PM
Harley Davidson, how did the boots fair? Were you injured at all? I've heard that primers can have enough power to blow off a toe and since you didn't mention that I take it you're OK.

Mike Irwin
December 16, 2003, 01:19 AM
They cry if you insult them.

They blow up if you start seeing other primers.

December 16, 2003, 12:21 PM
Lol. No injuries! :D I stepped on it on purpose after reading this thread, just to see if it would really go off. The was a black spot on the bottom of the boot - nothing else. Now I would say you can't set it off with anything soft - like a sneaker or even bare foot.

Oh, and I wore safety glasses when I stepped on it.

Zak Smith
December 16, 2003, 12:39 PM
I had a primer explode in my Dillon 650 just the other day. I was still getting used to the machine, and it requires a lot less force to seat the primer than my old SDB did.

Anyway, a large pistol primer going off is roughly comparable to a Black Cat firecracker, but with more flame. Definitely wear eye protection and don't put your hand over the case while seating the primer.


December 16, 2003, 12:40 PM
Vacuum cleaners are allergic to primers...causes intant death to vacuum, and all kinds of sneaking down hallways, yelling of woman folk and dogs barking...

December 17, 2003, 03:34 PM
I see you've been there done that TOO !!!

(sneakin down halls, dogs barking, women yelling !!! after suspicious explosions in the bullet factory !! aka -shop behind the house).

Smokey Joe
December 21, 2003, 05:12 AM
)Mike, you beat me to it! Primers are very new-age, cry easily at others' pain, can't stand the sight of blood, etc, etc.

Seriously, as I understand it, they are sensitive to heavy pressure like a cowboy boot on a concrete floor, and to impact. Impact, after all, is what makes 'em go bang inside the gun's chamber.

There is a story from WW II days that in some armory, a worker was carrying a metal bucket of rifle primers to the machine that seats them in the cartridge cases. He was jouncing the primers up and down in the bucket as he walked. When the dust cleared, they did find one of his feet, that's all.

Personally, though I can't reccommend it, I've vacuumed up both primers and smokeless powder with a hand-held, and with a shop-vac. They all get stopped by the filter bag, and don't get into the whirly parts nor the sparks. (I would NOT risk the same thing with black powder!!)

Once or twice I've accidentally seated a primer sideways in a primer pocket. Takes more pressure than usual, and you'd think I'd have noticed. (Guess I'm just not very sensitive myself! :D ) Anyhow, saved the cases in question by running them back through the resizing/decapping die, with great care, and with gloves, hearing and eye protection, and the primers, while thoroughly ruined, did not go off during the process.

Have had occasion to get rid of suspect primers, both in cases and out. Using hand, ear, and eye protection, the in-case primers were set off by putting the case in a vise and hitting the primer with a nail-set and a hammer (just like a gun's firing pin). The loose primers were set off by placing on an anvil and hitting with a hammer. Takes a fairly good blow; they don't go off with just a tap.

To sum up: Primers are explosive, and as such must be handled with due caution. Mishandling them can have serious consequences, especially mishandling a large number of them at once. When getting rid of them, protective gear should be worn on hands, eyes, and ears. But when care is used, they can be stored, handled, used, and disposed of safely.

December 21, 2003, 10:33 AM
*knocks on wood*

Haven't had any go off yet. I have had a couple get seated sideways and of course being squished in the process.

As far as how loud they are, I primed a couple .44 Mag cases with CCI Mag Primers, I believe, and shot them just to see how loud they are. About like a firecracker, so a bit loud without hearing protection indoors. I was surprised at the amount of sparks that came out the end of teh 5.5 inch barrel of my Redhawk! Good thing I was aiming at a bare concrete floor!

January 27, 2004, 01:02 AM
And Jeeper - I also read about someone that was vacuuming up some gunpowder aroung his workbench. He evidently also picked up a lost primer and it went off in the vacuum, detonating the gunpowder.

The gunpowder, unless it was black powder, would have been no factor.

Smokeless powder will just burn at atmospheric pressure. Kinda slowly.

You can try it (*disclaimer, I bear no responsability if you blow your head off doing this) just put about 1 teaspoon on a cement floor, and touch a (long, fire) match to it. About 2 seconds it takes to burn completely. Little hot flame. Done.

Primers on the other hand ARE an explosive, and a contact one at that. I am MUCH MORE FEARFUL of a bag full of primers than I am of a bag full of smokeless powder.

That said, it takes one hell of a jolt to set one off.

January 27, 2004, 05:00 PM
I've been reloading for over 35 years and have never set one off accidentally, and there have been cases of primers being seated sideways, etc. Picking up spilled powder with a vacuum is dangerous, most vacuums run the non filtered air past the motor, which could set the powder on fire, and a lot of vacuums run the air through an impeller fan, which could set off a live primer.

The story of the worker being killed by a bucket of primers is a bit of a reach, in manufacturing ammunition, primers are usually seated while the priming compound is still moist, making it extremely unlikely one could detonate while being seated, in that situation.

I have taken a very small amount of black powder, and a very small amount of smokeless powder and set them on fire, black powder goes off with a big "poof" with a lot of smoke when not contained, smokeless powder burns furiously!

January 27, 2004, 05:16 PM
We discussed this sorta topic a while back ....... and most has been answered.

I would tho suggest that the important aspect to primer detonation is impact ... SUDDEN impact. In other words ... tho a generalization .. the energy input must be intense in a temporal sense .... sustained weight for instance will probably not do it ...... it is a sharp tap that does it.

Maybe just now and again a disortion of the whole primer body can produce enough pressure of the anvil on the compound to initiate it.

For what they are .... they are very safe ..... but still need handled with utmost respect. Anyone who wonders about the noise etc .... don safety glasses and whack one with a hammer on an anvil or concrete (at arm's length) ... it is surprising what energy is released.

January 27, 2004, 11:11 PM
Blew a primer in my Dillon 650 too. Flashed accross the other primers in the wheel and up into the primmer tube setting off 40 more. Split the inner tube and drove the primer follower rod through the roof. The excellent design of the Dillon primer system saved me and directed all the escapeing chunks away from me.

Freaking tight S&B primer pocket.

Dillon refused payment and replace my entire primer system free of charge.

It was loud. Very loud.

January 28, 2004, 05:52 PM
If you drop one, don't let the cat get it, or the dog. Could be a bad play toy. :(

I spent an hour trying to scrounge up the last missing primer from a spilled 100 count tray of Federals, until I remembered that tray was one short when I opened the box. :rolleyes: It was still worth the effort, though.

At the rate I've been mangling primers lately, I'm thinking of wearing ear muffs when I reload. Haven't set one off yet, but...

Smokey Joe
January 29, 2004, 04:25 PM
I beg several of your pardons, but ALL of the modern vacuum cleaners I have ever dismantled, hand-held, shop-vac, canister, and upright, filter the dirt into a bag BEFORE the air goes near a fan or the motor. The dirt would do nasty things to the bearings if it routinely went through the fan, to say nothing of what would happen to an electric motor with dirt, sand, cat hair, etc, passing through it!

The one exception I ever saw was my mother's old vacuum when I was a little boy. It sucked the air and dirt up through a fanÑbut still not through the motor!Ñand blew everything into a large cloth fabric bag which had to be emptied periodically. That fan was made with plenty of clearance for small rocks, etc, which the machine might pick up. Even so, I wouldn't use a vacuum like that for primers.

The only ones I know of nowadays that work that way are the big parking-lot vacuum cleaners. Those you couldn't use inside a house anyhow.

I just can't imagine a scenario in which a primer could be struck sharply enough to be set off in a household vacuum cleaner of modern design. Or exposed to any sparks.

January 29, 2004, 04:46 PM
Don't Kirbys run stuff through a fan?

Smokey Joe
January 29, 2004, 05:14 PM
Big JimÑRe: Kirby vacuums; I couldn't say specifically if they run the dirt through a fan. (Not familiar with that brand.) If so, I certainly would NOT use one for sucking up primers, or anything else explosive.

January 29, 2004, 09:45 PM
I wouldn't trust any vac, modern or otherwise, to suck a primer unless I had looked inside it. I've opened a few uprights in the last several years (I need to get out more, I know), and they've all been very primer-unfriendly.

I thought I'd be really clever and use the ol' magnet-on-a-transitor-radio-antenna to get them out of the nooks and crannies they like to roll into, but...they don't stick. :uhoh:

Anyway, be careful with primers, but don't let them scare you away from reloading. If you're concientious enough to handload safely, you can be safe with primers, too.

January 30, 2004, 08:07 AM
good stuff. this thread's a keeper!

February 11, 2004, 12:24 PM
I have always taken at face value what I read in my commercial reloading manuals, and have been as careful as possible with primers... and so far, so good.

I use CCI and Winchester. Yes, Federal primers have several reputations, whether merely anecdotal or not I cannot say. These say they are both hotter and more sensitive than the other brands. Since I use auto primer feeds exclusively for pistol and for some rifle calibers, and since Lee SPECIFICALLY states that only CCI or Winchester primers should be used in their auto primer feeds. that's good enough for me. I have always gotten good results with the brands I use, so there is no reason I can see to use Federal.

I try to inspect the primer feeds in my presses regularly when in use, and have no more than one box of primers on the bench (what the feed mechanism will hold when full) at one time, just to be careful. Yeah, there are people who aren't careful, and I've known several who weren't, and they both got away with it. One was practically a textbook example of every bad and hazardous reloading practice you ever heard of- he kept loose primers in glass jars, he kept open coffee mugs of unlabled powder lying around his shop, and the guy smoked like a pile of burning tires during all phases of reloading....and was never scratched, died of heart failure. I almost died of heart failure several times watching him reload, too. You CAN get away with coloring outside the lines....but not forever, and I'd prefer not to tempt fate.

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