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Split Case - Any Ideas?

Discussion in '10mm Reloading Forum' started by atyszka, Nov 19, 2012.

  1. atyszka


    Aug 27, 2012
    Was at the range today testing some loads I'm working on and found these 2 cases early on. There were no others, but it's not that hot of a round so I'm surprised and wondering if anyone else has seen this. I wouldn't be concerned if this was the 3rd time for this brass, but they're brand new.

    New Starline brass
    Stock G20
    50F, 81% Humidity, 902 ft elevation
    165 gr GDHP
    15.6 gr AA #9
    CCI 350
    1311 avg fps
    1.255 OAL

    No other pressure signs (other than slightly flat primers which is always the case for me), case head is only .433


    Attached Files:

    Last edited: Nov 19, 2012
  2. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    That happens sometimes, brass may have been brittle in that area and as it stretched it split. Usually Star Line is soft and rarel splits like that, however I have seen many factory loads split their cases on the initial firing! Better case support can also help as the stock Glock chambers are loose.
    Good luck!

  3. Yondering


    Dec 3, 2011
    I agree with Shadow. Weird that it happened with new Starline brass, but with that load, I think you just got some bad brass. I've run into batches of Winchester and Lake City 5.56 brass that do that in factory ammo; sometimes it just happens.
  4. WeeWilly


    Nov 12, 2011
    I have had an occasional split on new Starline with my G20/29 loads. I think if you are getting more than a couple in a batch of hundreds, I would contact Starline and see what they think. I think my failure rate might be like 1-2 every few thousand.
  5. atyszka


    Aug 27, 2012
    Thanks for the insight guys. I've loaded tens of thousands of .40 and only see this on cases that I've shot 3-4 times. So I was surprised when it happened to a new case. I'll watch and if anymore pop up with mild loads I'll contact Starline. I ordered 1500 new and have shot about 700, so almost half way through the batch.
  6. SDGlock23

    SDGlock23 Glockoholic

    I had the same thing happen with some Top Brass I had at one time, lots of splitting going on.
  7. OregonG20


    Sep 5, 2011
    I've had new Starline do the same to me with 155gr and 180gr XTP's. CCI300, 1.26 COAL and close to book max charges of AA #9 as well. No other signs of pressure. No problems either.
    I think it just happens with Starline brass sometimes. Hasn't stopped me from shooting or changing my loads. YMMV.
  8. Taterhead

    Taterhead Counting Beans

    Dec 13, 2008
    Boise, Idaho
    The charge is certainly not a mild load. It is a tad over book max, but the brass is the culprit. Sometimes they are not properly annealed from the factory. It happens. Vertical splits in the middle of the case are not terribly problematic. Horizontal ones near the head are a different story.

    A small handful out of a box of a thousand will do that in my experience.
  9. AstraPat


    Mar 12, 2008
    Brass issue for sure. I would suspect the annealing process wasn't properly completed

  10. Kwesi


    Sep 23, 2006
    It happens to my 10mm Starline brass after numerous loadings. My nickel seem to last longer compared to regular brass.