can anyone explain why this may be happening

[Jeff2131]

These are beowulf cases.

..http://s911.photobucket.com/user/jef...5lhjt.jpg.html

This is happening with Factory and reloaded rounds. 335gr loaded with lilgun, mid range range load(i dont remember off the top of my head the exact charge weight). Ill get about 2-3 of these every 50 rounds. Not sure why its happening. The rifle is a build not an AA.

Any thoughts, questions?

[riflemen]

hate to say its the nature of the beast, a friend of mine has an aa upper, sometimes he gets 1 reload, sometimes brand new brass splits, if he reloads them light they last a little longer..
The only thing I can think of is if the chamber is oversized? do you have Headspacing gauges, can you check the size of you chamber...

[Unclenick]

The brass is curious. Who made it? It appears the extraction groove is lathe cut and not rolled, as is more common in production. I see Starline is making 50 Beowulf. Their brass is generally among the best quality, IME. You might call them and ask about it. See if they've had split issues reported. If your cases are already from them, ask about the issue anyway and see if they have recommendations regarding maximum expansion for good life.

Check the OD of the brass on new cartridges and on the fired ones. Typical SAAMI chambers hold the expansion of the body of a rifle case down to about 0.002". It is often bigger on pistol cases because they have to be resized about 0.002" under the diameter they will have over top of the bullet, in order to grip it, and then have their chamber expansion space in addition to that. The Beowulf more closely resembles that shape. If your cases are ejecting much bigger than that, it would suggest a loose chamber and is likely the source of the problem. Also check what size they come out of your sizing die and compare that to the factory new loads. It's possible to over-resize and make the issue worse.

I notice the splits stop at what looks like about half an inch forward of the extractor groove. That's probably where the brass starts getting thicker. One doesn't normally anneal cases with an aspect ratio that stubby because of concern about softening the head accidentally. But the old water tray method, with the water level up near that point may let you anneal down that split length and might prevent future splits. It may be work experimenting with, as the brass isn't cheap.

[Jeff2131]

I suppose i could look into head spacing...the bolt and barrel are only six months old. Machined together by satern barrels. I was think "nature of the.beast" also but its annoying because the brass is expensive and ya buy factory rounds to shoot to get the brass to reload and its splitting before you can reload it. Just has me shaking my head, been shooting and reloading for about five years now and never once had a single case split, ever. Thought its was me until the factory rounds did it too. Just wondering if people have ideas or answers.

[TMD]

Because its a straight walled cartridge AR's have an over sized chamber to help resolve feeding issues. Like riflemen said, nature of the beast.

[jmorris]

It looks like they are either too thin, sized more than they needed to be, or they were not annealed so they were too hard to expand without cracking.

Chamber issues aside.

[Jeff2131]

Now that u mention it...too.hard to expand maybe the.issue. i recall having one or two split like that while belling the mouth before seating. Maybe i.should try different.brass. doesnt starline make beowulf brass?