primer pocket blow out.???

[Lefty7mmstw]

Thanks .. alot and good information. ..
I just dont understand why it's happened hundreds of times in the 20 years on some of my ruger guns and there bolt faces look brand new.
And with that gun i know it was loose primers. I thought I could squeeze one more reload out of the casing.
And a little confused in why it's only done this to the Remington guns.?
I own several brands of rifles and these 2 new model 700s have been nothing but headaches.
I'm not trying to argue buy any means just trying to collect info and to prevent from future damage.

You really ought to rethink your load development or procedures if you have had more than a few blowouts. A few questions here... are you trimming your brass? over length brass can crimp and cause serious pressure issues.
Are you overusing your brass? You need to toss your brass when the primers no longer have a tight fit. Sloppy primer fit can sometimes cause blowouts.
What is your load work-up regimen? Are you using milder loads before top loads or going to 1 grain under and calling it? I've seen some rifles that can not take max. book load.

 

[MudRunner2005]

Check these threads out. Any chance you had a primer failure rather than a primer pocket failure. There seem to be several reports of WLR and WLRM failures recently. I am still waiting on the final report from Olin in regards to the prime I had that failed.

Nosler Reloading Forum • View topic - WLR primer UPDATE !!!!!!!!!!!!!!!!!!!!!

Nosler Reloading Forum • View topic - The downside to my last trip to the range

I think mine WAS a primer failure, but I use Federal 210 primers.

 

[Bob Wright]

I had a bad experience with Nosler 7mm mag brass this past weekend. Had 2 rounds breech the primer, primer pocket and gas blow back into the bolt face. The case head outside of the chamber had expanded .050 including the primer pocket. The primer has a pin hole in the indent, but along with that, the case was shoved back into the chamber causing the belt to get crushed/extruded to .050 width from .100.
Is it a loose primer pocket? I am waiting on pin gauges to confirm new and used brass for the pockets. Photo attached.

Scary....

 

[CaptnC]

That was not the brass at fault...that has all the classic signs of waaaaay over pressure. With it being new brass I doubt is was too long, but I feel you over charged that case...by several grains.

I can't recall the exact load, but I fired a case that looked exactly like that...went home pulled the bullets to re-weigh the powder charge. Like I said I don't recall the exact load but it should have been 47.9gr and I loaded 49.7 grains...case looked just like that!

Federal brass sucks...I've had a few leak just a little while the same load in Remington brass did fine.

 

[Bob Wright]

I have been shooting this load for three years. No heavy bolt lift and no abnormal primers flattening. What I am finding is so far, is my primer pocket unifrmer was .004 over spec, should be .127-.132, is actually .136. Second, loose fitting primer pockets in Nosler brass, reloaded average of three times, neck sized only: ordered plug gauges at .2085- .2100 per SAAMI specs for pockets. Not here yet...checking head space at local Smith and inspecting for damage. Powder measure of 27 rounds showed variation of .8 grains. Equipment is being shipped back to Pact for verification. Plan on making a change from Hodgdon 4831SC to Retumbo or other slower powder. I have shot 220 rounds with 100 or so in the suspect configuration with no failures or pressure signs. Then, kablooie..... scratching my head but doing my due diligence.

 

[Pdvdh]

Much pressure there. How'd the bolt face come through it? Did gases cut into the bolt face?

 

[Bob Wright]

Much pressure there. How'd the bolt face come through it? Did gases cut into the bolt face?

Absolutely no damage to the bolt face. I cleaned the rifle last night and was dirty outside of chamber. Here is another picture of cartridge. I also looked at SAAMI specs for pressure and it appears I am under the margin but it's still a hot load. 180 Berger at 2930 fps. Federal 215 primer.
I test fired five primers and indent is typical. Firing pin looks normal when pulled from bolt and fits bolt without slop. M16 extractor survived: no damage. Remington "3 rings of steel" worked very well!

 

[nmbarta]

Another thing to watch for is carbon build up in the neck of the chamber. Depending on how you clean your barrel, this area can be easy to miss.
Same thing happened to an STW that a friend of mine owned. He'd been shooting the same load for several years when he started blowing primers, he backed the load off and it still did it. The brass wasn't able to expand to let go of the bullet due to excessive carbon build up in the neck of the chamber, which created a dangerous over pressure situation.
Take a fired case and see if you can easily seat a bullet with your fingers, the bullet should go into the neck with no resistance, or just drop into case. If it doesn't, you have problems.
I don't know that this is a common problem, it happened at about 500 rounds.
Most people are guilty of a slight ejector mark, or maybe even a little bit of cratering on the primer when looking for a max load, but blown primers indicate that something is very wrong, and potentialy very dangerous.

 

[Bob Wright]

Another thing to watch for is carbon build up in the neck of the chamber. Depending on how you clean your barrel, this area can be easy to miss.
Same thing happened to an STW that a friend of mine owned. He'd been shooting the same load for several years when he started blowing primers, he backed the load off and it still did it. The brass wasn't able to expand to let go of the bullet due to excessive carbon build up in the neck of the chamber, which created a dangerous over pressure situation.
Take a fired case and see if you can easily seat a bullet with your fingers, the bullet should go into the neck with no resistance, or just drop into case. If it doesn't, you have problems.
I don't know that this is a common problem, it happened at about 500 rounds.
Most people are guilty of a slight ejector mark, or maybe even a little bit of cratering on the primer when looking for a max load, but blown primers indicate that something is very wrong, and potentialy very dangerous.

Yep, I just checked and it will slide into the neck with just a bit of drag.
I neck size only with Redding dies, and the correct neck die I had to order separately. I have 2, 1 for Nosler 1 for Remington brass.

 

[Bob Wright]

So, after all the great input, I looked at my primers that were in these two cartridges. Both are pierced. None of the cartridges fired left burn marks around the primer diameter, on the bolt face.
I'm leaning towards pierced primers.
What are all possible causes of pierced primers?
These are Fed 215.

 

[elkaholic]

I too would look for a carbon ring. It happens more often than people realize and sometimes is difficult to remove. I would clean as well as you can and then plug the neck/throat with a couple patches soaked in carbon solvent like you would find in a bike shop. Leave it in
for a day and check for a black ring, or partial ring, on the patch. If you see any color, ROTATE a brass brush with the solvent and patch again. I have seen this process need to be repeated for a couple days.
Another possibility is barrel metal going to crap in the throat! I saw this happen one time in a barrel having only 200 rounds through it. It was obviously bad
metal! It blew the primers with fire forming loads and we had to toss that
barrel. Good luck with figuring it out!.....rich

 

[elkaholic]

So, after all the great input, I looked at my primers that were in these two cartridges. Both are pierced. None of the cartridges fired left burn marks around the primer diameter, on the bolt face.
I'm leaning towards pierced primers.
What are all possible causes of pierced primers?
These are Fed 215.

I don't think a pierced primer would cause the case head to swell like that or leave that kind of extractor mark.

 

[Bob Wright]

This is a

I too would look for a carbon ring. It happens more often than people realize and sometimes is difficult to remove. I would clean as well as you can and then plug the neck/throat with a couple patches soaked in carbon solvent like you would find in a bike shop. Leave it in
for a day and check for a black ring, or partial ring, on the patch. If you see any color, ROTATE a brass brush with the solvent and patch again. I have seen this process need to be repeated for a couple days.
Another possibility is barrel metal going to crap in the throat! I saw this happen one time in a barrel having only 200 rounds through it. It was obviously bad
metal! It blew the primers with fire forming loads and we had to toss that
barrel. Good luck with figuring it out!.....rich

This is a stainless Krieger barrel, 26 inch with 221 documented rounds. I am really anal about cleanliness, but I will go back and double check the throat area for carbon. Who knows at this point?

 

[Bob Wright]

I don't think a pierced primer would cause the case head to swell like that or leave that kind of extractor mark.

Once the pressure got between the bolt face and head it shoved the cartridge forward. 050. Pretty violent. Without powder burns or pitting on bolt face and a nice clean hole in the primer....chicken or egg kind of thing. What failed first?