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Split a couple of cases today.

Discussion in 'The 10 Ring' started by OregonG20, Nov 20, 2011.

  1. OregonG20


    Sep 5, 2011
    Went shooting this morning. Fired of 50 rounds of my new load, which is:

    New Starline Brass
    CCI 300 primer
    14.0 gr's of Accurate Arms #9
    180 gr Hornady XTP
    COL = 1.26 inches
    Stock Glock barrel

    All 50 rounds fired just fine, nice and accurate and I never noticed a hiccup. After I collected all my brass, I found these two guys:


    Splits are in the middle, and don't go all the way to the top. I worked up to this load, and everything seemed fine. No flat primers, no excessive bulges.

    As you can see in this photo, the split is happening on the side of the case as it is chambered, not top or bottom. I don't have any experience reading primer strikes on Glocks, but I think it is occurring on the right side of the case, if you were looking down the gun just as if you were aiming.


    I don't see these as flattened primers. I know flattened primers aren't the best way to judge over pressure, but I am not seeing any crazy bulges either. Everything seems fine, other than these two splits. Are these rounds over pressure? Is it weak brass? While using my Lee factory crimp die, am I crimping too hard or not enough?

    Any thoughts or answers will be appreciated.
  2. Taterhead

    Taterhead Counting Beans

    Dec 13, 2008
    Boise, Idaho
    While that is a pretty warm charge for an XTP (Accurate has a max of 13.5), I would lean toward that being a defect of the brass. Splits like that are typically a brass problem rather than a pressure problem. Swampfox had an used withsome Top Brass a while back that were splitting like that.

    I agree that the primers look good, but I also agree that primers condition is not the best indicator of good-to-go pressures.

  3. cigarman454


    Feb 5, 2011
    Have to agree with Taterhead brass issue. I had one split today also it was a Federal cartridge 2nd fired case working up a load for some of my cast bullets well below book max.
  4. nickE10mm

    nickE10mm F.S.F.O.S.

    Apr 13, 2004
    Wichita, KS
    Those primer strikes look a bit cratered.... however, I saw this once before as being a brass issue. Still, tread with caution. That is quite the warm load, especially for a stock barrel. I would change the brass out and do another work-up with different brass to see.
  5. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    I see it a s a combination of brass and a potent load! Brass shows expansion very low at the web area, therefore the chamber added to the affect as well.

    This is exactly why we say that everthing is relevent and no two guns, barrels are alike when it comes to performance!

    Federal brass is know for splitting like that due to its brittleness. I don't accept this as being the brass by itself!
  6. 99blkta


    Jun 26, 2010
    Just out of curiosity, what is the expansion on the case. I'm aware this probably has nothing to do with the cracks, and all barrels are different; however, that area in picture 2 has an weird reflection to it, to me at least.
    Last edited: Nov 20, 2011
  7. oceanbob


    Jun 26, 2010
    I see the bulge..I see molten firing pin slots...I see split cases....I think you should back off .5 grain and call it good..:shocked:

    Take care, Bob
  8. rcd567


    Feb 5, 2011
    Near Glenwood, Iowa
    I've never met the man, although I hope to be in his will someday (he's building an airplane), I've read most of what he's written here and would heed his advice.:thumbsup:
  9. MinervaDoe


    Jan 26, 2009
    San Jose, CA

    The Complete Reloading manual for the 10mm and .40S&W has a copy of the Accurate arms load data. It's interesting to note that they have data for Speer 180 grain JHP and Hornady 180 XTP. It's the same weight bullet, but the Speer 180 grain JHP has a maximum of 14.5 grains :wow: with a PSI of 32,600
    While, the Hornady 180 grain XTP has a maximum of 13.5 grains with a PSI of 34,100.
    i.e. Accurate Arms recommended load for the 180 grain XTP is one full grain lower while its PSI reading is 1,500 PSI higher.
    Less powder, more PSI for the XTP.
    Last edited: Nov 21, 2011
  10. 21Carrier

    21Carrier Until I Gota 29

    Feb 4, 2011
    Hoover, AL
    Cracks like that are usually caused by brass that was not properly annealed at the factory. When brass is too hard it does not expand like it should, and just cracks. I had an old Federal case crack like that yesterday. It's no big deal when you're talking about old brass, but with NEW brass, it's somewhat bothersome. You need to measure your case expansion, and verify that it's still in spec. That load is pretty hot. However, I bet they would have cracked with a lighter load, as well. I would chalk it up to bad brass. The primers and strikes look typical of what I get from my Glocks.
  11. i have a tendency to agree with oceanbob
  12. Jitterbug


    Aug 27, 2002
    From the Accurate Arms 3.5 Edition.

    180 gr. XTP
    12.2 gr. AA9 Min
    13.5 gr. AA9 Max
    5" Barrel
    34,100 PSI

    The Hornady 7th lists 14.9 grains as max.

    If I were splitting brand new Starline cases, I'd back way off to start loads then proceed with caution. Check and double check again with dummies for setback issues.

    Recently I saw a thread listing all the "errors" in a well know reloading manual, quite a few. So always use two/three sources of published data and work up.

    I have some old AA9 I've been using in .44 Mag. Based on my velocity readings it's way hotter then the newer powder, despite Accurate Arms telling me otherwise and I've experienced the same results with other powders. Each and every lot has the potential to deviate.

    Moral, get a general consensus of published start loads and carefully work up.

    The brass might be bad, may not, then again it only takes one bad piece.
  13. Taterhead

    Taterhead Counting Beans

    Dec 13, 2008
    Boise, Idaho
    Every so often I will see splits like that with new brass - even at lower pressures.

    While I do suggest that the OP back down the charge (I bet those 180s are probably moving at a pretty good clip), I tend to agree with 21Carrier that a brass defect is at play. Vertical splits are not as worrisome as lateral case head fractures.
  14. gator378

    gator378 Gator378

    Jan 22, 2001
    St. Peters, Mo, USA
    Had a few over the years in 10mm, 44 Mag, 300 Weatherby,and some in 308. Usually brass that has been used several times. Usually load close to max. I never recall any splits in new brass, just reloaded many times brass.