Lapua brass failure

[moondog]

I ran my last BR Barrel pretty hard. The Brass suffered, but I knew it would. I've got 15 firings on that Brass and checking with a pick tool tells me it's done. It's getting thin in the web, but primers are still tight. Never seen a head separation like that! I don't even know how it could happen.

 

[HappyHellfire]

That is absolutely fascinating. I'm not a material scientist but I play one at work sometimes. Would you be willing to send me that case? Under the microscope you can see little details of the failure method.

 

[Dgd6mm]

My loads are somewhere around 2000 psi below maximum pressure. My sizing die is set for 0.002" shoulder bump. I confidently expect to get at least 30-40 reloads on my 6br Lapua brass. If I ran mine at the next node down I would expect more excellent life out if my brass. I very, very much doubt that the failure was due to a inferior piece of brass from Lapua. Usually it's US that cause our own issues.

 

[Tim Singleton]

have all the firings been in the same barrel?
kinda looks like unsupported case head
the cone maybe a little too deep and it showed up

 

[Bottom Fodder]

Have you checked on their unlimited firings life to warranty

 

[6.5 forever]

I think the title should be changed. That brass didn't fail, 30 times is wore out!!!

 

[Gunracer]

When you park your car, do you also go until you feel a bump and then gently back up a little?

just kidding, but you sure have way more "confidence" than me. Out of interest sake - how many reloadings were you expecting to get before you'd retire them?

I will keep reloaded a case until the primer pockets get loose or until there is indication of an upcoming case head separation.

 

[Murray Brook]

I will keep reloaded a case until the primer pockets get loose or until there is indication of an upcoming case head separation.

Pretty much what I do also.

 

[jxb]

Never seen anything like this before. I’ve had a few case head separations over the last 50 years but nothing like this. I guess even Lapua has its limits. I’ve been shooting this case since 2011 and this was its 33rd reloading. And no, there was no telltale “bright ring“ around the case.

Not saying this is normal case head separation (usually higher up), but one way to get an indication is checking the balance of your brass in that set.

Suggestion is when you clean your brass once every x firings bore scope the inside without the mirror on it. Just takes a second or two per and it will show you those that are starting case head separation where there is zero sign on the outside of the case. You'll know when you see one as the shadow is really obvious as soon as that part of the case is coming into focus. It's also a bit spooky to see how bad it can be and still not see any indication on the case exterior. Oh and while it's obviously easier to see it on wet tumble, you'll see it after media/dry tumble. It's one of those your eyes get big you step back and look again things.

How do I know this? I shoot 220 Swift and flat out. One rifle I was oversizing the brass and with a Swift it doesn't take many firings for it to show its ugly head. Looking at barrels is handy but that borescope paid for itself checking inside of brass.

 

[gunsandgunsmithing]

Probably just worn out brass but it has a significant ejector mark too, I'd double check everything and maybe back off a bit, especially if a different lot of anything. Looks a lot like pressure.

 

[JFrank]

I will keep reloaded a case until the primer pockets get loose or until there is indication of an upcoming case head separation.

What is the recipe you’ve been loading in those cases 33 times ?

 

[jpjulian]

How did your rifle fare after this episode?

 

[whatsupdoc]

That is not your standard caused by stretch case head separation but more like
too much tiger in the tank.

 

[Gunracer]

This was actually a 6BRX. I first shot 6 BR in Fclass. When the barrel wore out I replaced it with a Krieger in 6 BRX. I settled on 33.3 grains of Varget and a Berger 108 LRBT fairly quickly and shot it for years. When I got out of Fclass and moved to PRS style shooting I stayed with BRX because I had all the fixings. The load dropped way down for PRS and I settled on 31.8 grains of Varget with a 108 grain ELD-M (Bergers got too expensive). This brought the MV down about 200 fps to 2820. No tight bolt lift, no flat primers, no ejector marks, no case head separation. It was a new barrel for PRS.

 

[Keith Glasscock]

Definitely check the bolt nose to breech clearance, especially with it being a new barrel.

One of the skilled smiths here can give you good advice on how much is too much.

 

[YEW PLUCKER]

Never seen anything like this before. I’ve had a few case head separations over the last 50 years but nothing like this. I guess even Lapua has its limits. I’ve been shooting this case since 2011 and this was its 33rd reloading. And no, there was no telltale “bright ring“ around the case.

Egads!

 

[Old Navy]

Never seen anything like this before. I’ve had a few case head separations over the last 50 years but nothing like this. I guess even Lapua has its limits. I’ve been shooting this case since 2011 and this was its 33rd reloading. And no, there was no telltale “bright ring“ around the case.

Looks like an over pressured case. This is what impending separation looks like. These cases were fired 18 time in a 6.5X47L with safe loads. I found a couple like these after 16 firings and four or five at 17. I decided enough was enough was enough.

 

[jackieschmidt]

The fact that the primer looks fairly normal kinda points to the case head loosing support at peak pressure.

finding out how this happened is the big question. Two things come to mind. Out of battery firing, or way to much bolt nose clearance, leading to the web of the case being unsupported.

 

[LVLAaron]

I see no way the brass can be deformed that way if the case is/was supported all the way to the rim.

 

[Old Navy]

Never seen anything like this before. I’ve had a few case head separations over the last 50 years but nothing like this. I guess even Lapua has its limits. I’ve been shooting this case since 2011 and this was its 33rd reloading. And no, there was no telltale “bright ring“ around the case.

Did the bolt extract that or did you drive it out?