primer pocket blow out.???

[Bob Wright]

This is a

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?

Just checked the chamber, no tell tale ring. Hmmmm...

 

[Bob Wright]

This is a

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?

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.

Just checked the chamber, no tell tale ring. Hmmmm.

 

[Deleted member 46119]

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.View attachment 89735
Scary....

@Bob Wright I am glad you are OK. This could have been much worse.

 

[Deleted member 46119]

Federal brass sucks

We are all so different. I love Federal 308 and 30-06 brass.

 

[Bob Wright]

Thanks so

@Bob Wright I am glad you are OK. This could have been much worse.

Thanks so much! A good friend of mine blew up a custom 300 RUM. Barrel downrange 20 yards. Total scrap. Some facial injuries, nothing permanent. Lucky...

 

[Bob Wright]

Checked headspace: .001 using the bolt to seat a new primer. Cratering peaks on spent primers are .000-.007 above on 10 rounds fired before the cartridge breech. I might be on the ragged edge of pressure, regardless of past history of light bolt lift etc... Thanks for all your input friends! Time to start back at the beginning on hand loads and go slow. I don't trust this load.

 

[Bob Wright]

Inspected 20 out of a batch of brass from Nosler after about 3 firings using a no-go pin gage and 80% of my brass fails primer pocket diameter inspection at .210 diameter max per SAAMI. Guess I'm cleaning house and certainly will inspect all my large rifle primer brass in this manner from now on. I use a .209 dia. pin for a "go" pin, but the minimum is actually .2085 diameter. Primer seating by "feel" is pretty subjective.

 

[Pdvdh]

This much is for certain. You're overpressuring the case heads of your brass beyond its yield strain limit. Either got $hitty weak brass or your running above normal maximum load pressure.

Why you had one primer pocket blow wide open, 0.050" oversized, is up to you to figure out.

I lost a primer in Hornady 375 Ruger casing recently. But my primer pocket didn't open up 0.050" oversized. My primer pocket ID measured 0.215" and the primer OD measured 0.212" after firing this cartridge, which allowed the primer to fall free of the case head upon ejection of the Hornady case from the chamber. I'm done with Hornady brass. Now using RWS, and possibly Norma. Hornady is too inconsistent in case head strength, in my opinion.

 

[CaptnC]

We are all so different. I love Federal 308 and 30-06 brass.

I know this is not the "right" way to precision reload but my wife's rifle is sighted in at 100yds because we normally hunt in a very small controlled area. So when I was making brass for her 6.5-06 I was just grabbing once fired 30-06 brass without much attention given to manufacture. I ended up with roughly a dozen Federal cases out of 40 that I loaded.

I took it the range to make sure it was dead on. I normally put the fired case in the box head stamp up. I was playing more attention to the target than the brass when I noticed 4 cases had a little soot around the primers. Nothing like Bob had but a small amount of gas had leak back.

I sorted out all the unfired Federal cases because they were loaded as a "batch" loaded to gether just incase I had charged them too much. I got home pulled all the bullets and the charge was almost exact. None were over .2 of each other and the charge was right.

I'm a range brass rat...so my eyes are on the ground all the time. I picked up around 25 300wsm cases.

This week I was prepping all my WSM brass and was trimming brass when I found one of those pick ups had a split neck...sure enough...Federal! So they all went in the scrape brass bin!

PLUS the flash holes are nearly blocked. I have to get a drill out on one case to break the "chip" loose...

Winchester brass has cleanest flash holes on average, even compared to Lapua brass.

 

[nmbarta]

Jeez man, your buddy blew up a 300 rum? Your blowing primers? (That's more than a blown primer, that case looks like you were close to having rifle that looks like your buddies 300 rum)
I don't know anything about you or your buddy, and I'm not one to judge, but you guys have got to be more careful.
Your doing something wrong, that's what you need to take away from this.
Until you figure out what your doing wrong, you should stop.
If your loading reasonable loads and having that happen, you have other problems that you need to figure out.
Even sh*& brass won't look like that after a somewhat normal load.
Do what you want, but I'd take that rifle to a competent gun smith and have it scoped before I pulled the trigger again.

 

[Bob Wright]

This much is for certain. You're overpressuring the case heads of your brass beyond its yield strain limit. Either got $hitty weak brass or your running above normal maximum load pressure.

Why you had one primer pocket blow wide open, 0.050" oversized, is up to you to figure out.

I lost a primer in Hornady 375 Ruger casing recently. But my primer pocket didn't open up 0.050" oversized. My primer pocket ID measured 0.215" and the primer OD measured 0.212" after firing this cartridge, which allowed the primer to fall free of the case head upon ejection of the Hornady case from the chamber. I'm done with Hornady brass. Now using RWS, and possibly Norma. Hornady is too inconsistent in case head strength, in my opinion.

Yes these were in the upper end of pressure, but below SAAMI max cup pressure. I ran into the perfect storm last Sunday with a combination of things I covered in previous posts. I just think that this inspection would have given me a definite brass retirement point, had I done a no go pin inspection. I will never shoot one out of spec now. Lot of great new slow burn powders that are available but will be looking for lower speed, little less bullet weight. Found pin gauges online for less than 4 bucks each. Pretty cheap inspection that might help other reloaders.

 

[elkaholic]

Yes these were in the upper end of pressure, but below SAAMI max cup pressure. I ran into the perfect storm last Sunday with a combination of things I covered in previous posts. I just think that this inspection would have given me a definite brass retirement point, had I done a no go pin inspection. I will never shoot one out of spec now. Lot of great new slow burn powders that are available but will be looking for lower speed, little less bullet weight. Found pin gauges online for less than 4 bucks each. Pretty cheap inspection that might help other reloaders.

Over pressure for that particular situation does not necessarily have anything to do with saami!
I would not focus too much on the primer pocket being a little over spec either. I'm not saying that's ok, but you had signs of SERIOUS over pressure which could have resulted from a host of things, including brass, carbon ring, throat degradation, oversized bullets, etc., Etc. You were likely running a max load and something else was added to the mix...rich

 

[nmbarta]

Bob,
I get what your saying, but I'm not sure your getting what I'm saying. Overworked brass is harder than new brass do to work harding. If anything, it would show less pressure.....not more. Back before we were lucky enough to have this kind of knowledge at our fingertips, guys would use nail polish to hold primers in spent brass and keep shooting it. Primer pockets have nothing to do with that case looking like that. Something else IS wrong, there is no way to tell from here what it is, but I highly suggest that you figure that out before you move forward.
I read a lot on this site, but don't post all that much. I felt like I needed to say something here.
I sincerely hope you don't hurt yourself.
Good luck man

 

[Bob Wright]

Jeez man, your buddy blew up a 300 rum? Your blowing primers? (That's more than a blown primer, that case looks like you were close to having rifle that looks like your buddies 300 rum)
I don't know anything about you or your buddy, and I'm not one to judge, but you guys have got to be more careful.
Your doing something wrong, that's what you need to take away from this.
Until you figure out what your doing wrong, you should stop.
If your loading reasonable loads and having that happen, you have other problems that you need to figure out.
Even sh*& brass won't look like that after a somewhat normal load.
Do what you want, but I'd take that rifle to a competent gun smith and have it scoped before I pulled the trigger again.

That's why I spilled my guts on this forum at the risk I would get "tough" comments.
Here is what I know:
-The primer pocket uniformer tool was cutting .005 over max SAAMI spec for depth.
-The Powder scale is back to the factory for re-calibration after I found .8 grain variation in remaining loads I pulled.
-Brass was yielding in the primer pockets and out of limits after 3 reloads. Realize that I just inspected 50 brand new Nosler rounds, and these are only .001 under the max. Not much room for multiple reloads.
-There were no pressure signs in 100 rounds previous (but yet, here we are.)
-Below maximum SAAMI cup pressure for speed and bullet weight
-Head spacing still at .001
-No bolt face damage or powder burns
-Escaping gas blew the cartridge back into the chamber .050, then expanding the cartridge head diameter the same.
-Loose primers "may have" caused primer damage. Ultimately, they failed under unusually higher pressure and hot gas and this, I believe, started the train wreck. All decapped Federal 215 primers previously shot on this day were without incident and appear normal. Same load.

I'm glad my Remington 700 took the hit, because my friends was a Mauser type design, not the 3 rings of steel of Remington. I have 7 out of 9 lives left. Will be taking the barrel off for a muzzle break any way, so a full chamber inspection can be performed.
Hope this helps you understand I am doing my utmost to figure out this scary situation. I am not striving for "hot" loads, just accuracy and lethality at my capable distance.