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Split CASE!! Ideas

jplooksterjplookster Member Posts: 73 ✭✭
edited April 2009 in Perry Shooter Competition Shooting and Reloading Forum
New never fired Hornady 308 Win Match brass.
41.9 gr Varget 168 grain sierra match moly bullet. Charge Trickled and double checked before seating bullet.
COL 2.802.
BR2 primer

This brass weighs 25 to 30 grains lighter than IMI, Fed. Nosler

Fired in AR10 with 16" barrel

Happened to be cronographing at time of failure. Fired 3 rounds 2246 fps 2235 then 2210 on the split round.

1/2 inch vertical split at base of round just above head.

Same batch loaded round clocked 2500 fps out of 24" barrel AR-10
No pressure signs in any except the one that split.

????
I think defective Brass but now I'm leary of firing any more.
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Comments

  • jonkjonk Member Posts: 10,121
    edited November -1
    Probably just a fluke. It happens. Did the brass exhibit any other pressure signs? Flattened primer, etc?
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  • Tailgunner1954Tailgunner1954 Member Posts: 7,734 ✭✭
    edited November -1
    Split looks a lot like the capital letter "I"? Defective piece of brass. Most people call them "burn throughs".
    You'll also find the same kind of thing on necks and shoulders, and the answer is always the same. BTW, this type of problem is NOT a "pressure sign".
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  • RCrosbyRCrosby Member Posts: 3,808 ✭✭✭
    edited November -1
    Send it back to Hornady with all the specifics. They'll diagnose it and maybe even give you a bit of brass.
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  • JustCJustC Member Posts: 16,056 ✭✭✭
    edited November -1
    try annealing one or two and fire them to see if it happens again
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  • perry shooterperry shooter Member Posts: 17,105 ✭✭✭
    edited November -1
    Hello Just C but I think you missed the fact that the split was just above the head not near the neck I don't think you want to get the case head anywhere near the temp needed to anneal. do you. [?][?]
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  • JustCJustC Member Posts: 16,056 ✭✭✭
    edited November -1
    yep,..missed that fact altogether. definitely don't want to anneal a casehead[:0]
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  • 243winxb243winxb Member Posts: 264 ✭✭
    edited November -1
    quote:This brass weighs 25 to 30 grains lighter than IMI, Fed. Nosler Seems a lot to me.[url][/url]http://www.6mmbr.com/308Win.html Check out the brass section here. Does your case look like this one? [img][/img]http://i338.photobucket.com/albums/n420/joe1944usa/223_20090303_2.jpg My guess, bad brass with the light load your using. The 223 brass here was said by Hornady to be faulty LC brass. But the primer said high pressure.
    [url] https://saami.org [/url]
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  • jplooksterjplookster Member Posts: 73 ✭✭
    edited November -1
    243winxb,

    Yes it looks like the photo but the split is longer 3/8 to 1/2 inch long. No signs of pressure on any of the primers.

    The load was one step less than max as indicated in the Sierra manual. So I am not sure it is a light load. I think reduced velocity is due to the short 16 inch barrel and the fact that it was fired through a gas operated semi rifle. Moly coating may play a part as well. The same lot/load clocked 2500 FPS in a 24 inch AR10. Sierra says it should be a 2,600 fps load but that's in a turn bolt.

    Black hills new match 168 moly did clock at 2450 in the 16 inch barrel. So I do have some room to move the charge up.
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  • sandwarriorsandwarrior Member Posts: 5,453 ✭✭✭
    edited November -1
    jplookster,

    I had that exact same problem with some Federal .257 premiums I bought once. Two boxes from the same lot. The one piece of brass had a 1/2" vertical split about halfway up the case.

    I was chrono'ing the batch of shells to get an idea of what the velocity was from my rifle. I got the split and quit. I sent that piece in with the rest of the box to Federal. They came back to me with two extra replacement boxes of shells. Their explanation was that somehow during the manufacturing process something spilled on the brass and caused it to harden.
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  • jonkjonk Member Posts: 10,121
    edited November -1
    Just to add to the discussion, a split anywhere above the head isn't likely to cause issue. My concern would be, if the brass is brittle THERE there might also be an issue with the case heads themselves. I've had one case head burn through on firing- fortunately in a bolt action that held together. Even so it broke the extractor and mag follower spring, and doused me with plenty of hot gas.

    Now in a semi auto having the chamber open with ANY pressure left in the barrel could just make that a lot worse....
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