Thoughts on primer safety and toughness.

L

Lurch37

New member
As I was hand priming some 300 blackout today I got to thinking about how safe primers are. Invariably, I have the occasional primer not want to seat and most often it's due to a crimped primer case not being reamed enough. I never force a primer that feels off and simply remove that case to be reamed a little more or thrown away.

I also machine prime on my Dillon 550 and have had the occasional small primer 45acp brass slip into my tray, ( I do sort them out but I'm not perfect), which causes some concern when the handle stops abruptly on the upstroke. I also look at the bottom of each case before starting the process as well but again, I admit to missing a couple. I never force the handle priming on the 550 either but its a frustrating thing.

I have ordered new, primed brass from various online places and with a few of those, there doesn't seem to be a lot of packing around the bags. I can only imagine how much those cases, being loose in the bags are banging around while on the way to me.

And finally, I watch some loading videos here and there and some of these guys have auto primer fillers, much like a case filler, that while spinning has primers rolling all over and then dropping down tubes. They seem to be banging into each other a lot.

All this just got me wondering how tough are primers and how hard one would have to squish it or bang it for one to go off?
 
Primers are pretty tough, and not very susceptible to vibration caused failures either.

Lots of research and work since they were invented has been done to improve them, and eliminate failure inducing flaws.

In general, the chemical compounds used today must be crushed, sharply (meaning suddenly) in order to detonate. Crushing the pellet "slowly" rarely results in it going off.

In over 50 years of reloading I've had ONE primer pop in the press during seating, and that was long long ago, and entirely my fault.

I've crushed more than I care to admit due to things I didn't notice until it was too late, like being on edge in the primer cup. Never had one of those go off. I've seated some upside down, again, never had one go off.

Its not an uncommon practice to "recover" a primer from a case that got cracked or damaged (or a primer seated upside down) by SLOWLY using the press and decapping stem to push the primer out of the pocket.

Try the same thing with a decapping punch and a hammer and you won't enjoy the results. :eek::rolleyes:

Primers today are not as fragile as you seem to think. I don't worry about one going off as much as I worry about one not going off when I need it to. I always thought Capstick said it well, "the most frightening sound in the world is not the crash of a shell or the explosion of a bomb, but hearing click when you expect BANG,,,"

My experience is that if a primer failes to go off its usually improper seating. There are other things that can cause primer failure, but these days, you've got to work at it, usually.

I am speaking of primers made by reputable companies, (mostly US). Primers made in foreign countries by companies unkown to me, can be anything.
 
In over 30 years of handloading I’ve only had one pop, and that’s on my Loadmaster which is long retired. I will say one thing, I practically had to change my underwear when it happened. Those things are loud when you’re not expecting it. As far as why it happened I can only speculate, but it was a Loadmaster after all.
 
I started reloading in 1972. I have crushed them sideways, seated them upside down, dented them with an AR firing pin and decapped them. I have never had a primer go off.
I respect them, but I don't worry about them.
 
Me, three.

When I got my Freedom Arms .454 Casull the cases were for LPP; they converted to SRP and sent me small circular adapters (I forget what they were called) to insert and swage for the SRP. One day I fired a 300gr load and all it did was fizz. I found unfired powder so the primer failed to fully ignite the H110 probably because I didn't seat it properly. It was another look-for-new-underwear moment when I wondered where the bullet went and found it stuck in the barrel.
 
Like all the above, I have had small primer cases show up when loading 45's, the 550 tells me by the feel of the handle-when loading Sp or Lp I start the push slow, and keep pushing unless I hit a hard spot. That is a missized case. When loading mixed brass, Norma will cause you to mash like hell on the lever because they are about .001 smaller than our US brands, but not a hard spot-you get a two stage seating with Norma. I have done this many times with no issue- Unless you have a sharp impact, I think you're safe.
 
I seriously doubt I'll ever have a problem with small primer .45acp cases, as not only does each case get a visual inspection before going into the loading process, the last time I added to my .45acp brass stash was before small primer .45 cases existed, and I likely won't ever get any, since the few thousand cases I have will likely last the rest of my shooting life.

Since I passed my Tommygun on to my son, I just don't go through nearly as much .45 auto as I used to. :D
 
Seems like we all have had the same issues and everyone is no worse for wear. After looking at all the 10mm brass that's next up for processing, I get to sort large and small primers some more.
 
Primers are not easy to set off by mistake, or cartridges would be unsafe to carry into combat, but the odds of an accidental ignition still aren't zero. The reason live ammo and primed cases can be shipped without hazmat charges is the cases provide enough isolation that when one goes off, it doesn't normally set others off with it. This is not necessarily the case, however, with primers boxed together, which is why hazmat rules apply to them. They can exhibit concatenated ignition which is a chain ignition that occurs partly from the violence of an adjacent primer going off, partly just because open primer mouths allow heat and flame and sparks to enter and have a chance to get past the foil to the priming compound underneath, and partly because there is no large brass mass surrounding a loose or unseated primer to absorb shock, protect the open end of the primer, and soak up and draw heat away from it.

We had some photos posted in a thread awhile back of a brick of Winchester primers that had one end blown open in shipping and with a good number of the primers inside expended. This was interesting because the packaging did seem to have stopped them all from going off.

Another detonation reported more than once is of primers in a primer feed tube on a press going off. This is thought to be due to the owner failing to occasionally clean out the fixed primer feed tube on his press (a swab or long pipe cleaner and rubbing alcohol will do it), so primer compound dust accumulates that is set off by friction either during loading or when new primers start sliding in from a pickup tube. This has also happened in a pickup tube that got too dusty, too, and one photo showed one blown open in a couple of places. I'm glad I missed being present for that.

The bottom line is just to handle primers with some care and respect and to keep their handling equipment and surfaces clean. Do that, and the odds of a problem, if not zero, will stay very close to it.
 
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