M1A split case heads

[Shooter88]

Hello all.

Lately I have been getting a lot of cases split just above the head. I primarily use 150gr to 168 gr bullets, and use mostly IMR4895. Since my range does not go past 300 yards, I usually just stick with the minimum charge as stated in my reloading book. That being said, I think the cases are just getting old as the ones that are splitting I have reloaded around 10 times or so.

However it is really annoying when just the head gets extracted, and the next round that is stripped off the magazine is slammed into the other half still inside the chamber. This has sent me home early twice because I did not have anything with me at the range that could pull the broken end out (one time I had to take a .45 cal cleaning brush and through the chamber end push it into the broken case so that it would grip the inside of the case. I then ran a cleaning rod down the barrel until it hit the end of the brush and used a hammer to tap it out).

I always throw away brass where I can see a line (thin crack) start to form around the bottom, but a lot of the cases that have split did not show any visual signs (as in line/cracks. I dont know of any other visual signs to look for). Is there another way that I can test the brass to give me an approximate idea of how much longer it will be before a split?

[joelogic]

Unless they have been fired ten times it sounds like you have a headspacing issue.

[Shooter88]

Unless they have been fired ten times it sounds like you have a headspacing issue.

I'm pretty sure its because they have been fired so many times. When I say ten times I mean atleast ten times. I have newer cases and none of them have split, or are cracked.

[bumpo628]

You can use a bent paper clip to feel for the separation line inside the case.

[five.five-six]

You can use a bent paper clip to feel for the separation line inside the case.

yep

[Shooter88]

Well, I used the paper clip and ended up throwing out 20-30 cases. I think a lot of them I was being paranoid but I'm not going to risk anything. There were definately some though that were plain as day going to separate the next time they were fired.

Will they always have a thin line going around the bottom when they are about to break? Thats the problem I was having using the paperclip. Not all of the ones I checked had a line, but on some of those I was still able to feel a little dip with the paper clip. Those are the ones I think was being paranoid with. Oh well.

[Antihero47]

I would reevaluate how far your pushing the shoulder back on your reloaded rounds vs. what the dimensions in your chamber are. I hear a lot about people who reload their cases 6+ times usually end up getting split necks not case separations.

1 . Either your head space is off on your rifle and bolt combo and your in spec ammo is getting stretched after being fired in a sloppy large chamber.

2. Your rifles chamber and bolt are fine but your re-sizing the brass and your pushing the shoulder too far down. This may be causing a head-spacing issue when you load the brass into the rifle. When you fire the round it tends to want to stretch to take up the 'slack' behind the end of the cartridge and against the bolt. You may not be re-sizing the shoulder past the spec too much, but over 10x firings the problem has a chance to get to the point it breaks.


In my opinion, I would check the rifles head space. If it is deemed good to go by a gunsmith then I would use a case length gauge and drop some reloaded rounds into it. They normally have steps that will tell you if you didn't size your round enough or if you OVER re-sized the brass too much. If the ammo checks out OK through the gauge then I would just continue the paper clip tests after 4 firings. Keep testing them after each firing and once you notice any dip I would chuck them.

[bumpo628]

Well, I used the paper clip and ended up throwing out 20-30 cases. I think a lot of them I was being paranoid but I'm not going to risk anything. There were definately some though that were plain as day going to separate the next time they were fired.

Will they always have a thin line going around the bottom when they are about to break? Thats the problem I was having using the paperclip. Not all of the ones I checked had a line, but on some of those I was still able to feel a little dip with the paper clip. Those are the ones I think was being paranoid with. Oh well.

Why don't you use a band saw to chop one of the questionable cases in half? Then you can see how bad it really is compared to one that felt bad.

[FLIGHT762]

M1A's and M-14's (with a 7.62 NATO chamber) are very hard on brass and it is recommended that after four or so firings, the brass gets retired. You've reloaded your brass way too many times.

Read Zediker's downloads on reloading for the match M-14 and the Once Fired Twice Fired articles. http://www.zediker.com/downloads/m14.html

I've been shooting and reloading for my M1-A since the mid 70's.

If you want to set your dies to set back the shoulder a few thousandths for your chamber, turn the gas spindle to "OFF" and fire 5-6 cartridges and cycle the action manually, then do your measurements. The M1A and M-14 blows the shoulder a little farther forward during the extraction/ejection process. If you measure from normally ejected cases, you will get false readings.

[bruceflinch]

I'm pretty sure its because they have been fired so many times. When I say ten times I mean atleast ten times. I have newer cases and none of them have split, or are cracked.

Buy some new brass, ya cheap so & so!

[Endofcomment]

Buy some new brass, ya cheap so & so!

Bruce must be selling some more brass...

LOL

[Gunsrruss]

Normal Loads

Normal loads on M1A brass only last about 4-5 reloads. That's 42-44gr of 4895 at 2.84 OAL

[30Cal]

They're coming apart because you've shot them too much. You should have tossed them after 4 or 5 firings. If you don't know how many times you've shot them, then toss them.

Also, when you're cracking cases, you're doing your chamber no favors. If you've separated more than a handful, I'd recommend you have a smith take a look. 45,000+ psi hot gas directed through a crack will cut soft steel.

[Shooter88]

Well, I was going to go shooting today, but I ordered a case gauge and decided to wait until I get it and am able to test my remaining brass. I did not know they were only good for 4-5 firings. Next time I will be more mindful of that, and will mark each one in such a way as to tell me how many firings I have left. Can the same be said for 30.06 brass fired from an M1 Garand/1903A3/M1917?

Inside the chamber of the M1A, there is a black carbon ring that has built up where the cases split. I have pretty good eyesight and with a light shined directly on the ring, I cannot see a crack of any sorts starting to form.

[30Cal]

If they're being FL resized, yeah, I'd toss the 30-06 after 4 or 5 as well.