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Is This A Sign of Overpressure?

Discussion in 'Handloading and Reloading' started by DaisyCutter, Nov 9, 2012.

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  1. Krogen

    Krogen Member

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    'zactly! :)

    The case head is solid there. Sizing dies don't reach that area, so he's probably not "smushing" the case.

    Ken Waters used to (try) to judge rifle pressures by measuring case head expansion with a micrometer. In the following years, that method hasn't been well-accepted. Even so, Ken was looking for expansions of around 0.001" at rifle pressures. If DaisyCutter is truly seeing fingernail-detectable expansions in that area of a handgun case, something's definitely amiss; especially when it's not accompanied by sticky extraction or other issues.

    Never heard of this one before. DaisyCutter: Can you get some clear close-up photos of this area - before and after? It would be especially helpful to see the same particular case when new, just-fired and then re-sized.
     
  2. 918v

    918v Member

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    If the groove is disappearing, then you are correct, the pressure is excessive. Are you experiencing sticky cases? Cases get sticky at about 45000 PSI in a N-frame 357, prolly a lot less in a 44 due to thinner cylinder walls.
     
  3. CraigC
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    CraigC Member

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    If a Super Blackhawk is in danger at 40,000psi, then we're all in trouble. All you guys are doing is trying to justify the myth that pressure signs hold any meaning in straight-walled revolver cartridges. They do not.


    Gold Dots are NOT the same as plated bullets like Raniers. They sure as hell won't cause any issues at handgun speeds.
     
  4. Steve C

    Steve C Member

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    Mag primers will increase pressure with 2400 over standard primers. Note that the Speer data used standard CCI 300 primers. In my experience I have seen obvious pressure signs (pierced and cratered primers) in the .357 mag using 2400 with CCI mag primers and loads that where 5% below maximum. For 2400 I stick with standard primers or close to 10% reduced start level loads.
     
  5. DaisyCutter

    DaisyCutter Member

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    I'll get some better pics tonight.
     
  6. KevinR

    KevinR Member

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    I see the same thing all the time. I tend to look at the primer for all of my pressure indications. Holes burned through the primer, flat primers and so on.
     
  7. gamestalker

    gamestalker member

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    There ain't nothing wrong with that brass. But as already stated, stop using magnum primers with powders that dn't require it. If you were using H110 or 296 then a mag primer is needed to light that stuff up, but not for 2400.

    Using those powder charges you'll probably get 20-30 reloads from your brass. I use H110 and I still mamange to get about 20 cycles before I have to toss them out.

    GS
     
  8. armarsh

    armarsh Member

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    DaisyCutter - As it turns out, I have some unfired Winchester 44 mag brass. I took a close look at it and I noticed the relief cut is not concentric. It is deeper on one side than the other. Is that what you are seeing? If so, that is just the way it is made.
     
  9. armarsh

    armarsh Member

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    You might want to let Speer know that. Just so it is clear, my recommendation to find another bullet for full power loads has nothing to do with the trouble(?) the OP has with the cases.

    http://www.speer-bullets.com/pdf/ReloadingSupplementalDATA/44_200GD.pdf

    Note the part where Speer says that 44 cal Gold Dots were "Designed from the start as a low to medium velocity projectile..."
     
  10. CraigC
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    CraigC Member

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    You might want to recheck yourself. That's the sheet for the 200gr Gold Dot designed for the .44Spl, smart guy. If you were paying attention, you'd see that Speer #14 has data for the 210gr GDHP, the bullet in question, at up to 1600fps. I drive the 240gr Gold Dot near 2000fps out of rifles.
     
  11. DaisyCutter

    DaisyCutter Member

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    Here are some higher quality pics:


    As before, the 2 left are fired, resized, and tumbled... the 2 right are new.

    All are Winchester.

    8176691284_cd87b40611_c.jpg




    Below is a close-up of a brand new example, note the groove under the rim.

    8176685244_9e644a16ce_c.jpg



    Below is a representative fired, resized, and tumbled case. Note, not much left of the groove.

    8176654013_94ce6e9daf_c.jpg



    Here's a comparison of the heads, Used left and new right.

    8176684498_2be1bdd81c_c.jpg



    Going forward, I'll be reducing my charge or switching from the mag primers. Currently I have 400-500 mag primers to use up.

    Would you shoot the remaining 60-70 hot loads remaining if you were me? Versus throwing them away? Would you reuse the brass?
     
  12. 918v

    918v Member

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    Disassemble them.
     
  13. Krogen

    Krogen Member

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    Excellent photos, DaisyCutter. Sure shows what you've been describing. Clearly the metal in the groove is moving outward. And clearly, the case wasn't sized excessively as seen by the reduction in exposed rim. The diameter of the rim compared to the case body remained the same. The groove didn't! It's almost as if those are the old folded head design. But I'm sure they were long gone by the time the 44 Mag arrived. Could the brass be dead-soft in the head area? As in faulty annealing by the factory?

    I'll say I'm stumped. As 918v suggests, section one and see what's going on inside.
     
  14. bds
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    bds Member

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    When I saw the detail pictures, I went WOW! :eek:

    +1 on sectioning the case and can you post the pictures of before and after? Also, can you section other fired headstamp cases as comparison?

    Curious what the sectioned pictures show ... Thanks!
     
  15. Cosmoline

    Cosmoline Member

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    Something is sure going on there. Are the primers all cratered? Are the primer holes expanding?
     
  16. cfullgraf

    cfullgraf Member

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    DaisyCutter,

    If you have any loaded rounds left, have you looked at the groove in them?

    Did you look at the groove before running the fired cases into the resizing die?

    Maybe they were manufactured that way.

    Did they fit easily in the shell holder when you loaded them? Do they still easily fit in the shell holder?
     
  17. ArchAngelCD

    ArchAngelCD Member

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    After looking at those better pictures I changed my mind, there is something going on there alright. You might want to send a copy of those pictures to Winchester and ask them.
     
  18. CraigC
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    CraigC Member

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    Have you chronographed these loads? If the velocity is not out of line, you've probably got some overly soft cases. A charge of 23.0gr 2400 shouldn't cause any problems with bullets in that weight range but you really should switch to standard primers.
     
  19. DaisyCutter

    DaisyCutter Member

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    Chrony is on the short list, so I'll probably get one before I shoot any more from this recipe.

    BTW, could this be a function of too tight a crimp?

    I'll adress the other questions once I get some sleep.
     
  20. Slamfire

    Slamfire Member

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    How come you are not blowing primers?

    I don't like the look of your case heads. You are producing enough pressure to reform the exterior of your case heads. I agree Blackhawks are very strong and all that, but cases are not. It would be interesting to see a sectioned case and see if the inside of the case head has been thinned or the shape changed by the flattening of the extractor groove. Either one would be bad.

    I think your loads are too hot for the brass you are using and you should drop the magnum primer and cut your loads.

    This is what overpressure does to 45ACP cases that are not well supported by the chamber. Brass will flow at high enough pressures.

    Buldged45ACPcase2.jpg
     
  21. SSN Vet

    SSN Vet Member

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    post deleted

    meant to start a new thread
     
    Last edited: Nov 12, 2012
  22. floydster

    floydster Member

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    Wow!! I shoot a lot of 44Mag using 2400, Unique and 4227--never seen anything like this before, however I don't use mag primers, will be interesting to find out the cause.
     
  23. floydster

    floydster Member

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    Well, I checked several hundred of my 44 mag cases including Win, none have the groove expanded as in your photos, and I run some pretty hot loads using 2400.
    Seems to me it would almost be impossible for that to happen that far down on the case---just sayin.
     
  24. Walkalong

    Walkalong Moderator

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    Yep. As posted, have you checked the velocities you are getting? That is either soft brass or high pressure. If it is soft in the case head area it could be dangerous.
     
  25. NCsmitty

    NCsmitty Member

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    My guess is high pressure but not excessive, otherwise the primer pockets would start to loosen. Could be an issue with the brass and the clearance cut making the brass too thin in a critical area. Get rid of the magnum primers and/or drop the charge a bit.


    NCsmitty
     
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