What happened here

Speed3 · Apr 21, 2015

My dad was shooting fclass and this happened. Case split in half, not a hot load at all. Wondering why this happened? The neck got crushed because he tried to load another round, let the bcg go and smash.

Remington brass, 23.8gr varget shooting 77smks. We've fired probably a thousand of these with zero issue including Remington, lapua, and LC brass. First case I've seen like this...2nd firing according to a friend who gave them to me.

DaemonAssassin · Apr 21, 2015

How many times had it been loaded? Was it at the proper COAL?

Speed3 · Apr 21, 2015

DaemonAssassin said:
How many times had it been loaded? Was it at the proper COAL?

I edited the post, 2nd time but I don't know for certain since I was given these. 2.260 a few thousandths off but don't know off the top of my head, I always measure ogive.

Traveler · Apr 21, 2015

Looks like there was a crack in the case, leading to massive failure. According to the Hodgdon site, you are just slightly over max charge for that bullet.

BigDaddy · Apr 21, 2015

Inspect the other fired cases. Look at the 1st pic here: http://www.ar15.com/forums/t_6_42/325057_5_56_NATO__andamp_gt___223_Case_Head_Separation.html

The middle 3 cases are developing a line where the case on the left separated.
The cause in that thread is probably not the cause in your dad's case.

BigDaddy · Apr 21, 2015

Traveler said:
Looks like there was a crack in the case, leading to massive failure. According to the Hodgdon site, you are just slightly over max charge for that bullet.

Looks like 24.5g is a common load for this round over at AR15.com. I don't have a newer Sierra book to check.

Speed3 · Apr 21, 2015

Traveler said:
Looks like there was a crack in the case, leading to massive failure. According to the Hodgdon site, you are just slightly over max charge for that bullet.

Most are shooting a little hotter than that. It's just weird to me, maybe I missed a crack prior to loading?

Traveler · Apr 21, 2015

Bob at Maryland reloadr said you can bend the tip of a paperclip, run it inside the case, and find cracks that way.

Traveler · Apr 21, 2015

Hodgdon
Varget
.224"
2.260"
21.0
2,528
42,700 CUP
23.7C
2,737
50,700 CUP

http://www.hodgdonreloading.com/data/rifle

outrider58 · Apr 21, 2015

Traveler said:
Looks like there was a crack in the case, leading to massive failure. According to the Hodgdon site, you are just slightly over max charge for that bullet.

That sight can be very vague, sometimes. What does Sierra say? I have an old book that doesn't list Varget.

outrider58 · Apr 21, 2015

Traveler said:
Bob at Maryland reloadr said you can bend the tip of a paperclip, run it inside the case, and find cracks that way.

Good way to check for case head separation.

Biff_N · Apr 21, 2015

The Sierra book indicates 23.9gr as the max load for Varget.

Pinecone · Apr 22, 2015

Normally comes from over sizing or a chamber with excessive headspace.

Normally occurs closer to the base though.

The paper clip trick finds the thinning spot in the brass, before it becomes a separated case.

John from MD · Apr 22, 2015

Look for shiny lines around the case, usually closer to the case head. That is a good indicator for improper head space and incipient case head separation.

Your dad may be sizing the cases too much knocking the shoulder back too far. That combined with a chamber that is at max tolerance can cause case separations. +.002 here, - .002 there leads to a bad day at the range.

John

Melnic · Apr 22, 2015

John from MD said:
Look for shiny lines around the case, usually closer to the case head. That is a good indicator for improper head space and incipient case head separation.

Your dad may be sizing the cases too much knocking the shoulder back too far. That combined with a chamber that is at max tolerance can cause case separations. +.002 here, - .002 there leads to a bad day at the range.

John

position of the shoulder is too far down? Won't the sizing die max out when it hits the shell holder and not allow that?

John from MD · Apr 22, 2015

Melnic said:
position of the shoulder is too far down? Won't the sizing die max out when it hits the shell holder and not allow that?

It's all about tolerances. If your chamber is larger than the sizing die, each time you fully size the case you are pushing the shoulder back. There are tools that allow you to measure your fired case and adjust the sizing die appropriately.

John

FlatsFlite · Apr 22, 2015

Too much lube. It was pressed down down the die to that area and the hydraulic pressure created a thinned area of brass. I knew a guy who could crank these out at will. It would look like it was a precision cutx near perfect. If not, its something else.

89GLH · Apr 23, 2015

I run the same round with the same powder, @ 24.3 grains and my rig loves it. Never had an issue, and it's sent 1000+ to their demise into AR500.

Pinecone · Apr 24, 2015

Melnic said:
position of the shoulder is too far down? Won't the sizing die max out when it hits the shell holder and not allow that?

No. The die is designed to size to the minimum size specification. And if your chamber is not min size, you will oversize the brass.

toolness1 · May 7, 2015

Never seen it separate up that high if it is from headspace/oversized chamber/too much sizing

Interesting.

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