RPR BOLT BLOWN OUT

[Dusty Stevens]

I'd concur re: over-pressure. See how the brass flowed into the ejector - about 2:30-3:00 on the base?

If you had a stout load and the bullet got seated a little farther out and touched the lands.. might account for the pressure spike.

Glad you're OK!

A bad seating depth may raise pressure, but it doesnt blow cases. This is severe

 

[Nick Caprinolo]

Too much powder. Hard to understand what else could have caused it. What happened to the primer. Did you find it or just pieces of it?

 

[tobnpr]

A bit OT...
But since we're talking pressures, solids= higher pressures. Don't assume that "x" charge with a jacketed bullet will work with a same weight solid.

 

[Twdmar]

This would not be the first time a little pistol powder was left over in the recesses of a powder measure and wound up in a rifle case. And could a .277 bullet have found its way into a box of .264 bullets, surely not in this age of high demand/high production.

 

[JSH]

I myself see zero use for the pieces and parts you have left of the action itself.
If I were to reuse it, I would always have thoughts in the back of my mind every time there was any issue with it.
Scrap it and move on being thankful you never leaked any red fluid or lost body pieces or parts.

 

[Pres100]

This would not be the first time a little pistol powder was left over in the recesses of a powder measure and wound up in a rifle case. And could a .277 bullet have found its way into a box of .264 bullets, surely not in this age of high demand/high production.

If a .277 bullet was in the box and got seated into a .264 case neck that would be a pretty tight fit and would likely be pretty noticeable. The press has tons of leverage, but it would obviously distort the neck pretty good and wouldn't likely fit in the chamber would it?

 

[Twdmar]

If a .277 bullet was in the box and got seated into a .264 case neck that would be a pretty tight fit and would likely be pretty noticeable. The press has tons of leverage, but it would obviously distort the neck pretty good and wouldn't likely fit in the chamber would it?

Most likely it would be noticed but for that brass to flow into the ejector like that, it was more than just a few granules extra of powder or a bullet jammed in the lands. But then how many guys have shot a 300 blackout in a 223 or loaded a 30-06 into their 270?

 

[Ggmac]

Was it in a hard case or soft zipped case , first shot of the day ? You said the chrono was on , so maybe first shot soft case , stuff get into barrel as you slide the gun in . Always check , look thru bore before shooting. After dumping charges I use a flashlight to inspect each case for equal amount of powder . I weigh each assembled cartridge after reloading and inserting into ammo box . Any out more than a grain are sighters ( if im under max ) any out more are disassembled, any under 1 grain are sighters also .
I agree , the barrel is probably stressed beyond what Id consider using again , receiver is toast . Even if everything checks out you could be liable for any injury even 20 yrs from now . Withthe internet , everything lives forever given the right search and believe me attorneys know how to find this stuff . Plus you will never feel secure in squeezing the trigger . YOU ARE LUCKY , count your blessings , lucky stars , whatever , you and everyone around you are lucky . The firing pin and shroud could of found its way back to you .

 

[carlsbad]

yes. this was either a loading error or the barrel had a squib or other partial plug in it. --Jerry

 

[tobnpr]

I wouldn't assume the barrel is toast- what evidence leads to that conclusion?
Casehead separations unfortunately aren't rare occurrences- and tomato stakes aren't always the case.

I don't see any reason to suspect damage to the receiver- it's not like a lug cracked or sheared.
An overpressure load blew out the side of the case along with the extractor.

I'd inspect the receiver, borescope the barrel, and if all that checks out I'd get a replacement bolt and shoot it.

I don't see anything that tells me this barreled action is a tomato stake is a "given".

 

[lb-ft]

Metal of the receiver can be severely weakened and still look fine to the eye. The rifle isn’t designed for the 90,000+ PSI some have mentioned. I for one would sell off the good bits and keep the bare receiver on my loading bench as a reminder.

Yes it absolutely looks like severe over pressure. I have wondered though, can a defective, extremely weak case fail in this fashion at reasonable pressures and the damage RESEMBLE an over pressure round discharge event?

 

[jackieschmidt]

The bolt wasn't flawed. Just too much pressure. I'd say upwards of 80-90K PSI

^^^^^^^

 

[justpassinthru]

I wouldn't assume the barrel is toast- what evidence leads to that conclusion?
Casehead separations unfortunately aren't rare occurrences- and tomato stakes aren't always the case.

I don't see any reason to suspect damage to the receiver- it's not like a lug cracked or sheared.
An overpressure load blew out the side of the case along with the extractor.

I'd inspect the receiver, borescope the barrel, and if all that checks out I'd get a replacement bolt and shoot it.

I don't see anything that tells me this barreled action is a tomato stake is a "given".

What you stand to gain isn't worth risking what you might lose.
Some things just aren't worth taking the chance.

 

[jelenko]

Reading this thread reminds me of how casual we [or, at least, I] can get. Between practice and matches I go through 8K - 9K rounds a year. It's easy to just get into a routine.

Causing me to think about remaining aware of what I'm doing and is going on.

 

[Dusty Stevens]

Reading this thread reminds me of how casual we [or, at least, I] can get. Between practice and matches I go through 8K - 9K rounds a year. It's easy to just get into a routine.

Causing me to think about remaining aware of what I'm doing and is going on.

You have a bomb inches from your face and a roll of the dice whether it turns to shrapnel or not when it goes bad

 

[DaveTooley]

Metal of the receiver can be severely weakened and still look fine to the eye. The rifle isn’t designed for the 90,000+ PSI some have mentioned. I for one would sell off the good bits and keep the bare receiver on my loading bench as a reminder.

Yes it absolutely looks like severe over pressure. I have wondered though, can a defective, extremely weak case fail in this fashion at reasonable pressures and the damage RESEMBLE an over pressure round discharge event?

A case couldn't be formed in a fashion that would cause this. Nor could you get one case out of thousands in a lot to act differently. The yield point of the brass was exceeded and the brass flowed to the only opening. That being the extractor cut.

 

[Mike99-123]

Too much powder. Hard to understand what else could have caused it. What happened to the primer. Did you find it or just pieces of it?

Primer was intact. A little flattened and no piercing. I’m suspecting a failed case head. I had another piece of brass almost separate after the second firing.

 

[dogdude]

Starline brass, 4 firings, nuff said

 

[tobnpr]

Primer was intact. A little flattened and no piercing. I’m suspecting a failed case head. I had another piece of brass almost separate after the second firing.

Well, that changes things in my mind. I was on the fence as to whether it was severe overpressure or faulty brass; what did that brass look like that "almost separated"? For that to happen on the first reload is an indication of a real problem. Seems you've had this for a while- and assuming you've had no issues with other brass that would indicate an issue with excessive headspace I'd send that brass back to Starline to make them aware of it. Could save someone serious injury.

I'd still inspect the internals for damage, any plastic deformation of lugs or abutments to be sure there wasn't severe overpressure. That primer should've been flat as a pancake if it were overpressure.
And yes, I'm all about safety- but I still say there's nothing about this I've seen that would prevent me from putting a new bolt in it and shooting it after inspection of receiver and barrel. The bolt didn't fail, the brass did.

 

[Pres100]

I would think that as soon as the brass starts to deform around the primer pocket it's going to relieve some of the pressure on the primer itself as some of the gas escapes and not totally destroy it? The pic of the 300 BLK case that I posted had a flat but intact primer as well .... just fell out of the pocket when I removed the brass stuck in the the bolt.

The question in my mind is why didn't the gas take the path of least resistance out the front of the barrel .... which leads me to believe there must have been an obstruction of some sort that prevented it initially? The question really isn't if it was over pressure, but what caused the high pressure.

Other than powder charge, mix of powder and obstruction are there other potential causes of over pressure?