Ruptured case w strange marks

[ANARCHIST]

Bore sighted my rifle for this fall, had some old shells thought I would fire & get this on paper, make sure the scope was going to be decent.

First shot this was the results - never seen the dents in a ruptured shell in 36 years of shooting.

This is a rifle I have owned for 20+ years bought new I do not remember when, that long ago.

The shells are my sons old stuff he was discarding (no more reloading them)

load was 84.5 gr 7828 165 SBTHP 215 primer

Do I have a headspace issue or bad brass?

Shells had been used in a MK V previously this was fired in my Win70

Any thoughts? I do not have much experience with this type of situation as we are careful when reloading. These loads came from a RCBS Chargemaster which has been very good.

Thanks Guys

Rupturd Case Pics | JPEGbay.com

 

[Barrelnut]

First thought is the brass was reloaded several times with the case fully resized back to SAAMI specs. This can cause the case head separation above the belt after a while, especially on belted cases. That and the fact that your headspace may even be a bit more than the other rifle and bam head separation... Better practice on belted cases is to just bump the shoulder back .001 or .002 so the brass is not worked and thinned too much in this area.

The dimple at the front of the case was caused by not having enough pressure out the neck of the cartridge to seal the chamber. This allowed some gas to creep back and cause the dimple. The low pressure out of the neck was caused by loss of pressure out the back of the case due to the separation.

 

[ShtrRdy]

Yes, this sort of thing happens on belted magnum cases. I experienced one of these for the first time a few years ago. Now I'm very careful to only push the shoulder back as little as possible so the case side-wall doesn't stretch as much when it's fired.

 

[Pdvdh]

The shells are my son's old stuff he was discarding (no more reloading them).

Do I have a headspace issue or bad brass?

Thanks Guys

In addition to the explanations that have already been shared:
Extra-special precaution is warranted when reloading used/fired and especially, reloaded brass for the first time.

You might have an excessive headspace issue in your rifle, however I'd be surprised if it's a factory rifle with the original factory chamber. The brass is almost certainly bad, in order to get the full case head separation on your first shot. What's the reason your son was no longer reloading the brass? That could be the answer to the BAD brass.

 

[Michael Eichele]

That's common if shoulders have been bumped too far back and there are spring loaded ejectors.

 

[ANARCHIST]

The brass was old & my son bought a different cal rifle, I wound up with the old rifle & misc ammo - I am thinking as stated, old brass & headspace on Win70 may be a tad longer than the Mark V the brass was used in.

I fired my last 4 loaded virgin brass in the rifle after some replies here and no issues at all, it is a factory rifle never had any work done, I have had it many years, bagged most of my yearly buck with it over last 20+ years.

We will have to start partial sizing instead of the FL sizing as well.

The Win is CRF - I did notice one spot the head showed a shiny spot of a round plunger type ejector "Rem700 / MK V" that was after I fired the the shot I seen the bright spot.

 

[Kansaswoodguy]

Case head separation for sure. You can sometimes see a bight ring in that spot on the brass the firing before failure not always. I run a paper clip inside the cases and feel for it you can feel the thin spot. I had some creedmoor brass I bumped the shoulder to far back on and was having issues with this until I started only bumping the shoulder .003

 

[Pdvdh]

When you see the bright ring on the case exterior, you're not many shots away from failure. Best time to do that is right after the shot, rather than 4 years later. I also look inside the case neck with a flashlight. Pretty easy to see the shadow cup where the case web area has stretched. Easy to see even way before the case head is near separating.

 

[J E Custom]

All Good advice.

There are lots of reasons for case head separation. Excessive head space Of ether chamber, Excessive pressures, Full length sizing every time, Different chamber dimensions ETC.

It is recommended that belted cases be neck sized only because belted cases are sized small for
feeding and chambering in fouled/dirty chambers. The head space is controlled by the belt allowing for a very loose fit of the case body. Full length sizing should only be used when the round is tight and doesn't chamber well, And then size only enough to chamber.

Chances are that the brass has been full length sized every time it was loaded. I would not recommend using any of it and move on to new brass sized correctly for your chamber to avoid damaging your rifle/chamber.

Just my opinion

J E CUSTOM

 

[Wachsmann]

Had the same thing happen on a 6th loaded 300 ultra mag. It really set me back when I ejected the case. I did not know what to think. gun was less than a year old. I guess the sound was so different I had the guys on each side looking at me really weird as well. I was a shooting range when happen. After this I went home and started looking over all my brass. I trashed about 1/2 of my brass that had been resized 5 and 6 time. I noticed the little shinny ring on all the ones I trashed. Spoke with some other and most all only recommended 4 reloads at max with this round. Its been hard to get this rifle out shooting when every time I see the price on the new Nosler brass at 78 dollars a box per 25.

 

[tbrice23]

All Good advice.

There are lots of reasons for case head separation. Excessive head space Of ether chamber, Excessive pressures, Full length sizing every time, Different chamber dimensions ETC.

It is recommended that belted cases be neck sized only because belted cases are sized small for
feeding and chambering in fouled/dirty chambers. The head space is controlled by the belt allowing for a very loose fit of the case body. Full length sizing should only be used when the round is tight and doesn't chamber well, And then size only enough to chamber.

Chances are that the brass has been full length sized every time it was loaded. I would not recommend using any of it and move on to new brass sized correctly for your chamber to avoid damaging your rifle/chamber.

Just my opinion

J E CUSTOM

If full length sized correctly, moving the shoulder back .003 max, one should have no problems. I loose my primer pockets way before case thinning. I P.F.L. size all of my belted magnum cases every time.
After 5 loadings I'll start looking for signs of case head thinning so far no indication of excessive thinning.
Im on my 9th loading with very warm loads on a 300wm with Winchester brass. I even cut a couple of cases in half every loading to actually measure thinning.

This pic was taken after the 7 th firing.