Moisture In Primers? Failure to Ignite

[Hams42]

Longer dimension to shoulder = case cant be pushed as far forward off the bolt face by the firing Pin. I think that is what you're saying? Tighter fitting case = more reliable ignition.

By size better, you mean less right? Because sizing too much is what leads to the case stretch.

Those are pretty hard measurements to get accurately just based on the radiused nature of them. If you dont have a comparator to put on the shoulder, an empty 9mm case might work to use as reference to know how much you are bumping your shoulders when sizing.


My guess, is that the aftermarket brass, sized or not, is shorter to the shoulder datum than the factory ammo. Might be compounded by low FP energy or protrusion and harder to light primers vs what is in the factory ammo but I'd bet case size is a primary cause unless you can provide measurements compared to fired that paints a different picture.

I have heard of more stories of CCI primer duds than other brands but nowhere near the prevalence you're talking. Maybe a handful out of a thousand.

Great info. I will get on top of getting some of this.

 

[bluegrassdan]

The .400" datum line at the very middle of the shoulder is what you are "moving" when you size the brass. All that sizing really does is re establish the correct angle and the correct distance from the base of the brass to that .400" datum line and squeeze the rest of the case back to pre fired dimensions. Going off a reamer print or case print is only going to get you the dimensions as shown. Realize that that may represent the standard, but your chamber is almost always going to be slightly different because of many factors- tool wear, how accurate the chambering machinist was, barrel material spring back etc. There is a tolerance, very small, but allowable. That's why I say size your brass so the bolt just closes on a sized case, in your chamber, not to a set number. (yet) If you look at a standard .308 chamber and a .308 Palma chamber, there is a wide range of dimensions that have been changed over the years for many different reasons, so a reamer print is only good if it was the print of the reamer used in your barrel. When you get to the point where the bolt falls closed (no firing pin spring or ejector in the bolt) that is now your baseline for that brass, in that rifle chamber. Record all the same dimensions- base to datum, overall case length, diameter at the pressure ring just above the case head, neck wall thickness.... The base to datum does not have to be exactly the same as shown in the drawing, as long as you use the same method and tools to measure every time. A 9mm case, will have roughly a .375" diameter (It needs to be round) and the point it sits on the shoulder should be close enough if you use that one 9mm case as your gauge every time and never touch it for anything else. It will show you when you shorten that base to datum measurement each time you size your brass.

 

[Hams42]

....so I pulled the primer... and hit it with a hammer. Primer went off. If I do this again I will remember to wear ear pro....

 

[RealMuddyboots]

....so I pulled the primer... and hit it with a hammer. Primer went off. If I do this again I will remember to wear ear pro....

And safety glasses! All sorts of tiny fragments get launched.

 

[Jnasa]

....so I pulled the primer... and hit it with a hammer. Primer went off. If I do this again I will remember to wear ear pro....

or if primers fire in 2 other rifles take it that it’s likely the gun or brass as discussed? I guess now you know for certain.

 

[antelopedundee]

I was at the range yesterday and happened to find a 9mm round which didn't fire. looked like the firing pin strike was really weak. Case brand was I think R-P. Don't know if it was a handload. Are all Remington primers golden in color? There were other spent cases, some of which I picked up and threw in my scrap brass barrel.

 

[Hams42]

or if primers fire in 2 other rifles take it that it’s likely the gun or brass as discussed? I guess now you know for certain.

Just wanted to make sure. I hadn't loaded them up into another rifle for a while.

And safety glasses! All sorts of tiny fragments get launched.

And gloves my middle finger took some shrapnel.

 

[Wally Dog]

What do folks use for a desiccant? in Primer storage containers, anything to absorb the humidity

We have very low humidity generally so no need to concern myself with dessicant. I have primers that are 50 years old that work just fine.

 

[Hams42]

Longer dimension to shoulder = case cant be pushed as far forward off the bolt face by the firing Pin. I think that is what you're saying? Tighter fitting case = more reliable ignition.

By size better, you mean less right? Because sizing too much is what leads to the case stretch.

Those are pretty hard measurements to get accurately just based on the radiused nature of them. If you dont have a comparator to put on the shoulder, an empty 9mm case might work to use as reference to know how much you are bumping your shoulders when sizing. View attachment 379935


My guess, is that the aftermarket brass, sized or not, is shorter to the shoulder datum than the factory ammo. Might be compounded by low FP energy or protrusion and harder to light primers vs what is in the factory ammo but I'd bet case size is a primary cause unless you can provide measurements compared to fired that paints a different picture.

I have heard of more stories of CCI primer duds than other brands but nowhere near the prevalence you're talking. Maybe a handful out of a thousand.

So I used a 10 mm case because that should line up with the .400 line in the neck. I only had the ogive comparator tool.
Here is the findings.
Bad Primer Case 1.615"
Other Hand Loads that did fire 1)1.634" 2)1.636" 3)1.635"
Brand New Starline Brass 1)1.627" 2)1.627" 3)1.628"

So I think that this is my problem. I appreciate the tip and the advice.

 

[Wind Gypsy]

So I used a 10 mm case because that should line up with the .400 line in the neck. I only had the ogive comparator tool.
Here is the findings.
Bad Primer Case 1.615"
Other Hand Loads that did fire 1)1.634" 2)1.636" 3)1.635"
Brand New Starline Brass 1)1.627" 2)1.627" 3)1.628"

So I think that this is my problem. I appreciate the tip and the advice.

I think that’s your gremlin, glad to hear it sounds like you’ve got it figured out.

I’d use those 40 cal casings or get dedicated comparator inserts to avoid bumping the shoulders back anymore than you need to for 100% reliable feeding and you’ll get much better brass life and less trimming too.

 

[El Jason]

If you still want to discard the primers, I’ll dispose of them.

 

[Cemetery Sling Blade]

I know from experience oil, or too much oil really, will slow down a firing pin and cause light strikes. It seems crazy, but it does result in light strikes. Storing oiled guns muzzle up for long periods can allow the oil to seep into the firing pin hole.

I just recently started getting serious about humidity control in the gunshop. I got it to 40-45% now. Still, I put all my primers in GI ammo cans with desiccant from Amazon. It turns from orange to black when the beads are saturated.

I saw the cans that had ammo in cardboard boxes saturated the desiccant after a week of storage. Ammo stored outside carboard, the desiccant was still fairly fresh orange. The primer cardboard boxes are much thinner and I see there wasn't a saturated desiccant bag, but it does make me wonder if I should store them loose in plastic containers, like Berger plastic bullet boxes and the like.

Not that I'm worried they won't ignite, but I want them to ignite consistently for ES/SD.

 

[Hams42]

Okay so here we are again. I have had the gun is pieces since March when I ordered a new stock for it. After 6.5 months that was supposed to be 8 weeks I have my new stock. The new stock is great I love it actually. What I don't love is the fact that I am still having rounds fail to ignite.

This is new factory Peterson Brass all I have done is neck size it. I had three more rounds fail to ignite. I know its not the primer at this point. I know this because I've used about 400 of them in my 6.5 CM.

Last year I had Bergara send me a different firing pin and spring. After the three rounds not going off I swapped them. I should have measured the springs before installing them but the new one looks longer, while just eye balling them. Then I got my case gauge in the mail and found the following results. Here are two that didn't go off.

One slides in great the other does not.
I then put all the raw brass in and had no problems. Then I measured the other 10 I had loaded. 8 were perfect but two were not.

I colored the primer so I could keep them separate when I get around to fire them.

If I was bumping the shoulder back too much wouldn't it sit below the flush line? What may I be doing wrong to have 4 out of 25 not sit flush?

 

[Wind Gypsy]

I then put all the raw brass in and had no problems. Then I measured the other 10 I had loaded. 8 were perfect but two were not.

Can you clarify what the difference is between "raw brass" and the 10 that had been loaded? Virgin unfired brass vs fired and resized?

You may have an oversized chamber with excessive headspace (I dont remember if that was checked previously, didn't re-read the thread). Did you ever measure firing pin protrusion?

If your chamber is oversized, you might be sizing them but some still dont get down to spec for your gauge after a firing. If some cases stretched more, weren't lubed the same, had different levels of springback, or press was operated a little different you can have slight differences in dimensions after sizing. I dont think i've ever used a case gauge because generally speaking i only care how a case fits in the chamber it's being fired from.

 

[Hammsolo]

I’m an over doer. I started using a hand primer and would squeeze the handle until it touched. I smashed a shit ton of primers… I thought touching would give me a clear consistent variables. I may try to put a sharpie mark on my tool as I think about it… think…

 

[Hams42]

Can you clarify what the difference is between "raw brass" and the 10 that had been loaded? Virgin unfired brass vs fired and resized?

You may have an oversized chamber with excessive headspace (I dont remember if that was checked previously, didn't re-read the thread). Did you ever measure firing pin protrusion?

The raw would be virgin brass. I usually just neck size with the virgin brass. The other 10 had been neck sized and loaded but are still unfired.

I had done the head space with the brass that was bad and that had fired in the past. And had found the bad ones were short. I will pull the bullets when I get home and measure again to see. From the sounds of it maybe i do have a over sized chamber. The measurements previous on different brass are 4 or 5 posts back.

 

[Hammsolo]

The raw would be virgin brass. I usually just neck size with the virgin brass. The other 10 had been neck sized and loaded but are still unfired.

I had done the head space with the brass that was bad and that had fired in the past. And had found the bad ones were short. I will pull the bullets when I get home and measure again to see. From the sounds of it maybe i do have an over sized chamber. The measurements previous on different brass are 4 or 5 posts back.

I have Peterson Brass for my 7 prc. I read that their brass is set to load, annealed and everything.

 

[Hams42]

I have Peterson Brass for my 7 prc. I read that their brass is set to load, annealed and everything.

Yeah they are the only brass that doesn't need any prep work. I probably dont even need to do the neck size. I have never had an issue with any other peterson brass. And since I have had the issue with peterson, startline and Hornady I either have my dies set up wrong or the gun has an issue.

 

[Hams42]

9kay so using the 10mm measuring brass I got the following numbers.
Virgin Brass 1.63"
Once fired brass 1.635"
Dud rounds 1.627" and 1.629"
Firing pin protrusion is 0.073"

So I must have full length sided a couple. I guess I will back the die up some more and then fire form some brass. Because even after firing im still in spec.