Expanded case head

[josh.rizzo]

I was load testing 308 with brand new, never fired, Lapua brass (resized it once anyways for consistency). I was doing 3 shot groups of each charge weight and I noticed randomly blown out primers in one of the shots in a group. There were no pressure signs at all on the other shots in that group. This happened on loads that were no where near max and some were almost at starting loads for my data.

I reloaded several rounds at the same charge weights that I saw problems on, as well as some weights that appeared fine. Sure enough, about 1/3 would blow out a primer, or at least show gas leaking around the primer. There was no correlation to any specific charge weight that I could figure.

I changed from Winchester primers to CCI primers and the problem went away. So, I assume it was either a bad primer batch or Winchesters large rifle primers just suck period (never used them before).

The worst part is exactly 1/5 of my brand new brass is now unusable. When I went to resize and prime them after cleaning, the case heads are so expanded that they no longer fit in my shell holders. Many of them won't even hold a primer.

1. What is the likely cause of the brass heads expanding? Can I assume it was the bad primers causing high pressures? Or is it possible to get a bad batch of Lapua brass? Anyone seen this problem before?

2. Is there any way to FIX the brass? I considered freezing them to see if they would contract, but figured I would check for ideas here.

 

[Shynloco]

Now that's weird. I use Winchester primers all the time to fireform my brass which is either Lapua, LC (all three versions), Norma or Federal. In fact, I was firemforming some once fired LC Nat'l Match just today in my .308 and no pressure, no blow primers, no nothing other than relatively reasonable groups @100 yds using IMR4350 at a mid range load pushing some old Hornady 168gr HPBT's. I'd like to see how others diagnose your issue. But I think your bad brass is toast and it would be suspect to being bad if the primers were already "leaking gas" from new primer pockets.

 

[dkhunt14]

No way to fix them, they are done. It sounds like over pressure to me. Bad powder; wrong powder; fat bullets or maybe a hundred other causes. I wouldn't think a primer could cause it unless a magnum primer might make a load to hot. More info is needed. Carbon buildup in throat could cause excessive pressure. It the primers fell out after 1 firing you are at dangerous pressure and need to find out why. Matt

 

[Shynloco]

No way to fix them, they are done. It sounds like over pressure to me. Bad powder; wrong powder; fat bullets or maybe a hundred other causes. I wouldn't think a primer could cause it unless a magnum primer might make a load to hot. More info is needed. Carbon buildup in throat could cause excessive pressure. It the primers fell out after 1 firing you are at dangerous pressure and need to find out why. Matt

+1

 

[37Lincoln1]

Winchester had some problems with their large rifle primers.

I had the same problem with them in different calibers that used large primers, most in Lapua brass but some Winchester and Remington as well. Do an internet search and you will find threads about this with pictures of the primers with a hole in the top edge of the primer. Bad part is these bad primers etched the bolt face.

http://www.calguns.net/calgunforum/showthread.php?t=623587

I contacted Olin customer service talked to a Tech and they were aware of the problem. They had me send the bad primers to them with the damaged brass, blown primers and unfired rounds.

They took care of me immediately with no hassle.

 

[fdshuster]

37lincoln1: I had blown primers with Winchester Large Rifle, in a 308, loaded with a moderate load. Very tiny pin hole at the top curved "bend" of the primer cup, resulted in burn holes on a bolt face that prior to that could not be told from new. I stopped after the second one blew, so damage was minimal.

Switched to CCI200, and federal 210 & 210M, actually with hotter loads, same rifle, and never had the problem again.

When Winchester first brought the plain brass primers on the market one of their advertising claims was that they were "easier to ignite" since they were not nickel plated.

I won't be using Winchester primers again.

 

[jlow]

Bad Win primers may cause pierced primers and etched bolt face, but I would agree with dkhunt14 that the primers should not cause the over pressure that cause the case head over expansion. OP needs to look a bit more at his other components and especially at the charge weight.

 

[amlevin]

I won't be using Winchester primers again.

I quit using them years ago after the first experience with their quality.

 

[jonbearman]

Why dont you post your exact load and rifle you were using at the time.

 

[josh.rizzo]

Why dont you post your exact load and rifle you were using at the time.

Using a brand new Savage 10 with a broken-in 24" heavy factory barrel. Bullets are 210gr Berger VLDs seated .01" off the lands. Using brand new Lapua 308 WIN brass. Powder is IMR 4320. I saw the primer issues around 38 grains. The load data Berger sent me for these bullets listed IMR 4320 at 37gr MIN and 39.5gr MAX. The loads at the blown primers only clocked at around 2200fps and the blown primer rounds clocked the same as the others in the group, so I'm fairly sure it wasn't overcharged. After switching to CCI200 primers I got up to 41gr/2500fps before I saw any pressure signs and stopped (some barely noticeable primer cratering).

After reading this thread and some other posts I'm fairly convinced it was a bad batch of primers. It just seems weird that the case heads expanded the way they did. It wasn't a problem with the new brass because they got sized primed just fine the first time, but now many won't even fit in shell holders. The brass doesn't look stressed or cracked anywhere...the case heads are just noticeably too big now.

 

[jlow]

Are you sure about the 0.01" off the lands, that could do it to you in terms of pressure.

 

[mikecr]

Sounds to me like a chamber/breech/bolt fitting issue.

How much has a fired web area grown over unfired.

 

[Shynloco]

Winchester had some problems with their large rifle primers.

I had the same problem with them in different calibers that used large primers, most in Lapua brass but some Winchester and Remington as well. Do an internet search and you will find threads about this with pictures of the primers with a hole in the top edge of the primer. Bad part is these bad primers etched the bolt face.

http://www.calguns.net/calgunforum/showthread.php?t=623587

I contacted Olin customer service talked to a Tech and they were aware of the problem. They had me send the bad primers to them with the damaged brass, blown primers and unfired rounds.

They took care of me immediately with no hassle.

I noted that the post 37Lincoln1 referred to was posted in 9/12. So that gives you a time frame for potential bad Winchester Large Primers. I just checked those that I have and fired yesterday and none had "pin holes" and my bolt face was not affected. Good part is I'm down to my last 150 Win LR primers and I'll be going to Federal or CCI primers when those run out.

But Josh, your post was certainly one that many can learn from and save us some headaches in the future. Hope Winchester makes good on those Lapua cases that are also getting tougher to locate. Good luck and holler if you need help. BTW, did you consider just trying a different brand of primers and see what the result was with the same procedures used with the Win LR primers? Just a thought.

Alex

 

[josh.rizzo]

Are you sure about the 0.01" off the lands, that could do it to you in terms of pressure.

Positive. I used a modified case to chamber a long round and seat it with the lands. I got a COAL of 2.881" from that. I loaded a regular case at 2.880" and it did not make any marks on the bullet when chambered. I set a final COAL of 2.870" which is where I tested my loads at.

 

[LHSmith]

I was load testing 308 with brand new, never fired, Lapua brass (resized it once anyways for consistency).

Pls. explain exactly what you did to "resize" new brass and why?

 

[josh.rizzo]

Sounds to me like a chamber/breech/bolt fitting issue.

How much has a fired web area grown over unfired.

I'll have to check with my calipers when I get home, but 80/100 fired cases still fit in my Lee shell holders with a little wiggle room left. 20/100 cases won't even go into the shell holders with a hammer now.

 

[josh.rizzo]

I was load testing 308 with brand new, never fired, Lapua brass (resized it once anyways for consistency).

Pls. explain exactly what you did to "resize" new brass and why?

I just ran it through my RCBS 308WIN FL sizing die (with an expander ball on the mandril) like I would anything else. Saw a guy from Lapua recommend doing that in case they got squashed a bit on the ride from the factory.

 

[josh.rizzo]

...BTW, did you consider just trying a different brand of primers and see what the result was with the same procedures used with the Win LR primers? Just a thought.

Yes, I switched to CCI #200 primers; everything else was exactly the same except it was about 5 degrees warmer outside on the second day. I it up to 41 grains before even the slightest pressure signs this time. No blown primers or problems of any kind with the CCI stuff.

 

[jlow]

...BTW, did you consider just trying a different brand of primers and see what the result was with the same procedures used with the Win LR primers? Just a thought.

Yes, I switched to CCI #200 primers; everything else was exactly the same except it was about 5 degrees warmer outside on the second day. I it up to 41 grains before even the slightest pressure signs this time. No blown primers or problems of any kind with the CCI stuff.

So are all the cases that had over expanded case head came from the Win primer equipped rounds and none of the CCI primer equipped rounds had any problem?

 

[LHSmith]

Are you sure about the 0.01" off the lands, that could do it to you in terms of pressure.

Positive. I used a modified case to chamber a long round and seat it with the lands. I got a COAL of 2.881" from that. I loaded a regular case at 2.880" and it did not make any marks on the bullet when chambered. I set a final COAL of 2.870" which is where I tested my loads at.

You should repeat that method several times. The individual bullets will vary in tip to ogive length. Plus if you were in minimum headspace region(due to the die adjustment), you could have some at jamb. Also those heavy VLD bullets probably extend well into the case body, and the powder may be pushing them out over time.