Media in Case vs Pressure

Discussion in 'The Ammo & Reloading Forum' started by steve4102, Dec 17, 2011.

  1. steve4102

    steve4102 Former Guest

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    What if anything would happen if there was a few grains of media left in a 223 case then loaded and fired?

    The load in question is a 223 Rem, 65gr Sierra bullet, 25gr H-4895. The powder with this load comes just to the base of the shoulder. In the case with the left over media the powder was almost to the top of the neck.

    Could this bullet/powder/media combo cause a catastrophic failure or enough pressure to blow the case apart?

    My research tells me that it would be difficult to get enough H-4895 into a 223 case to case a KB let alone a mixture of powder and media, but I've been wrong before.
  2. LDBennett

    LDBennett Well-Known Member

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    steve4102:

    If the media is stuck in the bottom then the primer may not be able to ignite the powder. The bullet leaves the case and starts through the barrel but stops part way. I had this very thing happen when I used to use a media polish. The media would clump up and one of the clumps dried up in the bottom of the case. Media stuck in the case that might block the primer hole is a real problem if you de-prime first then tumble the brass. Besides that, you subject the sizing die to dirty brass which can scratch the working surfaces and transfer that damage to subsequence cases size in that now damaged sizing die.

    LDBennett
  3. jack404

    jack404 Former Guest

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    LD you may have explained a mystery ..

    i added a few drops of "Brasso " brass polish to some walnut , that batch sucked

    i've done it a few times before but probably added too much, none ever since .. and been fine


    Thank you !!
    Last edited: Dec 18, 2011
  4. LDBennett

    LDBennett Well-Known Member

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    jack404:

    I use walnut shell media in my Dillon vibratory brass cleaner and NO polish. I clean my brass not for looks but to protect my sizing dies. In my opinion there is no NEED for bright polished cases. A semi-stain finish is adequate. The carbide sizing die imparts a bit of a shine through the burnishing action the sizing die gives the case. That is adequate for my needs. Adding polish to the media is risky as both you and I found out the hard way.

    As an aside, I gave up on corn cob media as it is a better polishing agent than cleaning agent. It also does not seem to last as long as walnut shell media. I think the walnut shell media in my Dillon unit is several years old and still does the job and it has cleaned many bucket loads of brass.

    LDBennett
  5. Country101

    Country101 Active Member

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    Steve, I think too, that if you are referring to the media taking up extra space and having a normal charge, this could be bad. I dont reload, but from what I gather from these fellas posts occasionally is that the pressure will be a lot higher with the lower amount of space in the cartridge. That would make it dangerous.

    Correct me if I am wrong here, fellas.
  6. steve4102

    steve4102 Former Guest

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    NO, you are not wrong. But is the reduced case capacity from what I described enough to cause a catastrophic case failure?

    OK here's the deal.

    A fellow handloader had a catastrophic failure in his Mini-14 a few months ago and he never found the cause. The case looked like this.
    http://charlie6.org/c6forum/download/file.php?id=340

    A few days ago he was loading for his Mini-14 with the same load and a new powder measure. All powder drops were consistent and they all filled the case to the neck/shoulder junction. All but one, this one case had powder up to the top of the neck. He dumped the powder and charged it a few times and each time the powder was up to the top of the neck. Upon further inspection he found media stuck to the sides of the case. Not packed on the bottom, stuck to the sides.

    He concluded that the previous KB was the result of media stuck to the sides of the case.

    I don't buy it. In my experiments a full case of H-4895 weighs 27.2gr. Hodgdon lists 26gr as Max with a 69gr bullet. QL calculates 27.2gr with his 65gr Sierra bullet at just under 64K psi. This load will not produce enough pressure to destroy a case like the the picture above.

    If a full case full of H-4895 can't produce enough pressure to KB a case, how can a load that is part powder and part media produce this kind of pressure?
  7. oldgunfan

    oldgunfan Member

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    I made a depriming die out of and old noncarbide 45acp die and the decaping pin for a 300win mag that I had bent because the primer hole wasn't in the middle. any way when I need to clean some brass I use that to decap then I put them in a Hornady sonic cleaner for 20 or 30min's then if I wan't them real shinny I put them in the tumbler for 2hrs with a 50/50 corn cob walnut mix. LDbennett you might wan't to try one of thoughs sonic cleaners, if you don't care if your brass is very shinny. they just clean the brass real good and that's all.
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