what causes bad primers?

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sequins

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I just experienced 7/50 CCI small pistol primer failure to detonate. I got good, well centered firing pin strikes and tried each round twice, once DA and once SA in my GP100. I fired about 100 other reloads that worked flawlessly from other batches.

What do you think caused these to fail?
 
Proper seating of the primers “ arms” the primer so that it will detonate when struck by the firing pin. Makes sure you are seating the primers firmly so that the primer anvil is positioned properly to fire consistently.
 
1. Are you sure you actually removed the old primer and put a new one in the brass? It happens more than you might think.

2. Not seating the primers correctly.

I've loaded close to 100k rounds in my life time, rifle, shotgun, and handgun. I can count the number of "bad" primers on one hand without using all my fingers.
 
Yeah it seems really odd that the fault is not somehow with me, but these were wet tumbled clean 38 spl cases and I'm sure it was fresh primers. My only thought is somehow I got oil on the primers but no idea how. I still have more in the brick of 1000 I loaded these from so I'll monitor the further loads from this lot. I think they were properly seated but maybe that too.
 
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I have read multiple threads where people actually tried to kill primers with oil, water, and a variety of other chemicals.
None of these methods (even submersion and sitting) worked reliably; most had absolutely zero effect.

I think your problem lies elsewhere.
 
My experience has been similar to 243winxb. In 40 years of loading I got my first last year, I disassembled my dud and found a primer cup void of compound. Ever since then I keep a keen eye on them in the flipper much as I do when scanning the powder charge in my cases. But that's too many in one outing, I'd give that Ruger a good cleaning and maybe a fresh hammer spring.
 
What do you think caused these to fail?
Likely tip of anvil was not properly pre-set against the priming compound.

If the brass is mixed range brass, primer pocket could have been modified/reamed/swaged deeper and require deeper seating as simply seating primer to flush in these brass may not pre-set the anvil tip against the priming compound.

I think they were properly seated
Different brand primers have different shape/tip/height of anvil and the tip must be pre-loaded/set against the priming compound for reliable ignition -
https://www.thehighroad.org/index.p...-and-discussions.778197/page-10#post-11386382

Proper seating of primers is a 2 step process
and if you stop at Step 1 with anvil tip not pre-loaded/set against the priming compound, initial striker hit may not result in primer ignition rather seat the primer deeper, possibly setting the anvil tip against the priming compound for subsequent primer cup strike to ignite the priming compound.

Step 1 - The initial resistance you feel when seating primer is primer cup being pushed down the primer pocket. Depending on the primer pocket depth, seating primer cup flush may not set the anvil tip against the priming compound.

Step 2 - The secondary resistance you feel is primer anvil feet bottoming with primer pocket and sliding up inside the cup to pre-load/set against the priming compound (.004" below flush) and face of cup deforming (.008" below flush).

Ensure the top of primer cup is .004" to .008" below flush and see if you get same failure to go bang problem.

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I loaded these primers on a forster co-ax and all were 0.005" beneath the case rim. I've never had problems before in thousands of rounds.
 
But the cases that experienced primer misfires, have they changed?

If they are mixed range brass, measure the primer pocket depth and you will find they can vary, possibly requiring different primer seating depth to properly pre-set the anvil tip against the priming compound. ;)

If primers are indeed properly seated to pre-set the anvil tip against the priming compound, it could be something else like firearm related but I would ensure the primers were properly seated before I start changing gun parts.
 
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Yeah it seems really odd that the fault is not somehow with me, but these were wet tumbled clean 38 spl cases and I'm sure it was fresh primers. My only thought is somehow I got oil on the primers but no idea how. I still have more in the brick of 1000 I loaded these from so I'll monitor the further loads from this lot. I think they were properly seated but maybe that too.

The one time I had several bad primers was when I wet tumbled and the cases were not completely dry.
I guess a tiny amount of water was still in the flash hole. Loaded them in the evening went to shoot in morning about 1/3 no bang.
 
I just experienced 7/50 CCI small pistol primer failure to detonate ... I fired about 100 other reloads that worked flawlessly from other batches ... these were wet tumbled clean 38 spl cases
The one time I had several bad primers was when I wet tumbled and the cases were not completely dry ... Loaded them in the evening went to shoot in morning about 1/3 no bang.
Were other 100 round that "worked flawlessly" wet tumbled also?
 
I started handloading 17 years ago. Many, many bricks of 1000cnt primers from all the brands have been bought. Never had a dud yet.

Thought I got a bad batch of CCI small pistol once. Turned out to be a weak spring in a Ruger SR9C.

Light springs and hard primers don't mix well.
 
It is possible you seated them to hard and broke the primer pellet.
Unlikely.

I have read reviews where primers were seated to crush depth of .008" below flush which prompted me to repeat the test from .004" below flush to .008" below flush.

All the primers went bang.

So don't feel bashful and seat those primers hard.
 
It is possible you seated them to hard and broke the primer pellet.
I have worried about that myself. Sometimes I'll set one hard, still not flush and crush it until flush or a little past, squishing the primer almost till it looks fired. They still go bang. Maybe 1 in 30 or so have shallow pockets. IIRC mostly mixed 9mm range brass.
 
Seems to be the biggest thing that these diagnose my bad primer posts have in common. Wet tumbling, or is that just my observation? Not to say that wet tumbling is the root of all problems, but it seems to be in a bunch of them. Primers failing to go off, cases sticking to powder funnels, seating problems because cases are too clean, etc. etc.
 
Unlikely.

I have read reviews where primers were seated to crush depth of .008" below flush which prompted me to repeat the test from .004" below flush to .008" below flush.

Oh, I think you and the other members are probably right about that and what the OP's problem is.
I've seated some of mine hard and worried about hurting the primer and they always went off.
I was used to Winchester primers and got a hold of some Remington 5 1/2s and they seemed to have a longer skirt on them, I couldn't get my usual seating depth with them and I forced them pretty good.

I didn't want to admit this to anyone when I did it, but I had 12 primed 38spls that I mixed in with my dirty .357mags by accident and ran them through the ultra sonic cleaner for 16 minutes with citric acid and Dawn detergent.

When I discovered this I set them up on a shelf out of curiosity and left them dry for a month and they all fired. I couldn't tell a difference between them and new primers.
The things are tough!
 
The brass seemed dry to me when I loaded it. I think I'd washed it days ago and I highly doubt wet tumbling somehow caused this unless dawn residue might somehow be the culprit?
 
The brass seemed dry to me when I loaded it. I think I'd washed it days ago and I highly doubt wet tumbling somehow caused this unless dawn residue might somehow be the culprit?

Wet tumbled with the old primers in or out?
 
I thought my brass was dry it looked dry was on a towel for 2 days.
Some of the duds were very obviously wet when pulled.
 
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