What would cause a case to split!!!!??

[kaseyfied]

alright people,

I come to you for advice lol. long time reloader, many calibers. working up a load for a friends 338 edge that he just had put together a month or so ago. specs are as followed.

remington 700 action
barletin? (spelling) 26 inch barrel with DE break
40x trigger sey at 2.5 pounds
mcmillian a3 stock ajustable cheek and LOP
seeking ext box mag 3.900 COAL
oversized recoil lug.. holland I believe
all work done but gunsmith

alright, to the question at hand so this am I loaded 85-91 grains of h1000 1 grain steps for pressure test. fed215 match primers and remington 300rum brass necked up to accept the 338 bullet.. I shot the 8 rounds this morning with no pressure signs at all. but I did see some flattened primers on a couple of rounds. 86grains and again at 90 grains, but all other rounds had no flattening what so ever which was weird to me. So went back home and loaded 21 rounds to do a round robin ladder test for vertical spread at 700 yards. went out to the usual spot. setup the bullseye cam and the target. get all setup, pop a round at 88grains into the chamber, get behind the trigger, saftey off and BOOM. something didnt sound right. I eject the round, and it came out in 2 peices. one peice was 2/3 and the other peice was about 1/3 lol.. im confused. no pressure signs at all, no reason for this to happen at all. SO I come to the reloading gurus for advice lol.. any help would be great. oh and bullets were loaded .020 off the lands for a coal of 3.035 to ogive. overall length of 3.840.. thanks in advance myfriends

kasey field

 

[royinidaho]

A clarification question.

The case separated 2/3rds of the way from base to neck, as in head separation but further up the case?

If so, excessive head space might be considered. Some thing would have to set the shoulder way back for this to occur.

However, you said "split" which I can't even imagine.

Pics of case would be appropriate.

Oh, just because it was built by a gunsmith doesn't carry much water, with me. My wife just went through a repair surgery because a surgeon botched the first job. Ramifications are similar to your situation.

 

[kaseyfied]

right right lol.. I just was saying that I didnt put this rifle together in my garage on a sunday afternoon. so I guess the case isnt really split.. its in 2 seperate pieces completly, it came out of the chamber in 2 peices.. it broke apart about 1/3 of the way up from bottem to top.. and left the upper 2/3 of the case intact. no neck split or anything like that.. thanks again

kasey

 

[375fan]

How many firings on the brass?

 

[g0rd0]

a few questions
like above how many fireings on the brass?
was the brass that you used to expand the neck to 338 old or new?
after you expanded the brass did you anneal it?
can you get a led light into the chamber and have a look? It is possible that if the smith who installed the barrel may not have polished it and there may be ring in there sufficient enough to split the brass. A cheep way to check that is to load up a round coat it in soot or machanics blue chamber and fire, the brass will show any defects in the chamber

 

[kaseyfied]

I sized the brass with a 338 madrel from sinclairs.. and it had 1 firing on a brand new case. the case didnt split. I got 2 complete seperate pieces of brass when I extracted the shot brass from the chamber. the bottem 1/3 blew off the remaining 2/3 of the upper piece of brass. so the smaller piece almost looks like a 45 ACP lol. its crazy.. not sure I really wanna shoot it again the barrel was a used barrel I bought from a good friend that had 150 rounds down the pipe. so it was just threaded to the action and headspaced I hope atleast lol I did not anneal the brass after. I anneal after 4 firings at the least

kasey

 

[HARPERC]

If so, excessive head space might be considered. Some thing would have to set the shoulder way back for this to occur.

Definitely on the check list before it's fired again.

 

[kaseyfied]

so maybe I sized the case too much.. I made sure I left over 0.100 on the case when I sized it.. pretty sure in didn't bump the shoulder any or very little

kasey

 

[Bullet bumper]

If the brass is new then the best thing to do is reduce the load down 10% for the first shot and jam the bullet into the lands but don't extract before firing . This way the case head will not expand backwards . That should blow the shoulder forward taking up any excessive head clearance .
That should fix the problem for that batch of cases while you only have to neck size but as soon as you need to body size it may cause the same issue again if the chamber is cut too deep and a standard die will not reduce the base to fit before it bumps the shoulder .
You keep sizing to fit the case back in but by the time it does fit the shoulder has been bumped too much .
I would definately take it back to the gunsmith and ask for the head clearance to be checked again and make sure you take the head seperated case with you and a few of the other new unfired cases and mention that you think the gun is dangerous .
That should motivate them to check it out properly .
If the chamber is in spec then the suspicion falls on the new brass or the sizing system .

 

[tbird1964]

The only rifle I have had that happen on was a Colt Sauer that had to be replaced because of excessive headspace. The factory sent me a brand new rifle in the box.

 

[HARPERC]

The only rifle I have had that happen on was a Colt Sauer that had to be replaced because of excessive headspace. The factory sent me a brand new rifle in the box.

We had one in .375 H&H, I believe that rear, retractable lock up flexed under pressure.

 

[tbird1964]

I think that is why they quit making them. I had another one in 25-06 but I never felt safe shooting it and sold it several years ago. I never had any problem with it but I just did not feel comfortable after the problem with the first one. Smoothest action rifle I ever had.

 

[HARPERC]

Smoothest action rifle I ever had.

That's why my partner bought his, and as good looking a stock as you find on a factory rifle.