Pierced primers????*update*

Noel

Noel

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Okay, I'm trying to get ready for my sheep hunt with my trusted 7x57. I am using full length resized brass just like every other time from my Hornady dies.
I am using the same brass as always and the load has not changed at all. I used it last fall with great results accuracy wise and in function of the rifle.

Why do I get pierced primers now?

Brass is trimmed, neck sized 6mm brass that has long since been fireformed. Primers have nice radius edges, no sign of pressure on extraction or measurements.

The striker looks identical to the one in my 8x57 which is almost new.
I have never seen this before and am buffalowed.

Looks like I will have to lug my 9,3 on the 7 day hunt now, not very cool.

Thanks for your help.

Noel
 
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I was thinking about this after you left tonight Noel. Why not try a primed case with no bullet or powder, just to see.

I just had a quick look and most of what I found we already know, But something to look at anyways :confused:

primers2.jpg


The primers at the right show increasing pressure as you go up. The bottom primer was fired with no projectile/powder. Notice the rounded firing pin impression and primer cup edges. Next one shows primer semi-flattened, still rounded corners, a very tiny crater. The third shows well cratered primer, more flat, less rounded cup - on the verge of piercing. The top shows a pierced primer. Depending upon the temperature sensitivity of your powder and differences between test and 'deployment' temps, stay within the lower two primer states. If you test in cool weather loads that are to be used in hot summer months, and you see serious cratering, you can count on pierced or blown primers (primers that unseat). Pierced primers will discharge gas thru the bolt, and cause firing pin damage.
Click to expand...

Also here:

http://www.jamescalhoon.com/primers_and_pressure.php
 
Noel said:
Okay, I'm trying to get ready for my sheep hunt with my trusted 7x57. I am using full length resized brass just like every other time from my Hornady dies.
I am using the same brass as always and the load has not changed at all. I used it last fall with great results accuracy wise and in function of the rifle.

Why do I get pierced primers now?

Brass is trimmed, neck sized 6mm brass that has long since been fireformed. Primers have nice radius edges, no sign of pressure on extraction or measurements.

The striker looks identical to the one in my 8x57 which is almost new.
I have never seen this before and am buffalowed.

Looks like I will have to lug my 9,3 on the 7 day hunt now, not very cool.

Thanks for your help.

Noel
Click to expand...

Noel, Did you change brand or type of primers? My 6.5/300SM will pierce CCIBR2's, but not Federal 210M's.


NormB
 
I am still using CCI 250's Norm. Everything is the same as last year.

It is a different lot of primers. The 250's used to have a yellow primer compound under the anvil, now it is a pinkish orange.
Maybe I will try backing the load off.

How much should a striker protrude from the bolt face?

Noel
 
The other posibility is your original load was always hot, but you just never saw signs of it in your brass or primers. It is possible too that the changes from lot to lot (primers or powder) have increased pressure of the rounds.
I'd try backing off by half grain increments to see if that fixes anything.
 
crazy_davey said:
I am willing to bet ya cash it is not the firing pin.

:D
Click to expand...

It isn't yet anyway..:D

While they are backed off a fair bit from where I tested to find the max in my gun I am going to try backing them off more as mentioned.;)

I was very happy to find Sibbald empty today but for one Elderly Chap getting ready for season. I enjoyed a nice visit with him, then put the VXIII on my 9,3, bore sighted it and tested at 30yds. Perfect bullseye first shot.:) And no primer grief either.;)

Aside from all the skin tore off my elbow from recoil I am ready to shoot the biggest ram on the hill. However, if I get some proper rings located at WSS tomorrow maybe I can still pack the 7mm like I hope. I like the 9,3 but oh Mylanta it is too burly to carry on the scree that long!:runaway:

After the shopping it's off to "the Place" for a feed of Ribs with my wife.:bigHug: You and Renae going to show up Dave?

Thanks for the help Gents!:rockOn:
 
Noel, what was the load that was piercing primers and what did you back down to???
I'm not looking to try your loads out in my 7x57,I just wanted to know how much you backed down the load??
 
I just took one grain out and it all straightened out.
I am using H414 so I wonder if the higher humidity this year is wreaking havock?????

As to specifics I'd have to check my data and get back to you.
 
Here's a thought... I had a .308 once with a loose chamber, "max" headspace but still OK when checked on a gauge. If I fired factory loads, or handloads with new brass, no problems. No trouble with neck sized reloads. But if I full length resized the brass, I was getting pierced primers. My theory is that I was full length sizing too much, and pushing the shoulder back even more. The primer backed out when the round was fired, then the case stretched to re-seat and in doing so pierced the primer. I adjusted my dies to just kiss the shoulder and the problem went away, and brass life increased. You may want to consider that.
 
Noel said:
I just took one grain out and it all straightened out.
I am using H414 so I wonder if the higher humidity this year is wreaking havock?????

As to specifics I'd have to check my data and get back to you.
Click to expand...


I'm not a big fan of CCI primers, I use Federal LR and magnum primers in a bunch of different calibers and never had one pierce. I have had several failures and piercings of CCI, so I stopped using them altogether.
 
savagefan said:
Just 1 grain?, "Livin' on the edge"
Click to expand...

That is where I left it when my (1) scope potentially piled, (2) my supply of bullets and powder ran out and (3) on the next day I had to leave on a trip.

It will likely be started over from scratch once I get my scope back from warranty or put another one on it. Last year I had worked up beyond what I use as a hunting load by quite a bit with no grief at all. Perhaps I got a bad batch of primers, I've never had any trouble with CCI since switching from FC, actually they seem better aside from this adventure.
 
Longwalker said:
Here's a thought... I had a .308 once with a loose chamber, "max" headspace but still OK when checked on a gauge. If I fired factory loads, or handloads with new brass, no problems. No trouble with neck sized reloads. But if I full length resized the brass, I was getting pierced primers. My theory is that I was full length sizing too much, and pushing the shoulder back even more. The primer backed out when the round was fired, then the case stretched to re-seat and in doing so pierced the primer. I adjusted my dies to just kiss the shoulder and the problem went away, and brass life increased. You may want to consider that.
Click to expand...

Longwalker, that is a good point to consider. I was using resized 6mm Rem brass as I have done from the start and it may have had the shoulder back too much for my 7mm chamber. I always full length resize since I hunt more than target shoot with my ammo. I will try to re-adjust the die for next time.

Thanks,
Noel
 
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