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What is the diameter of .223 primer pocket?

Discussion in 'Handloading and Reloading' started by mugsie, Jul 16, 2007.

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  1. mugsie

    mugsie Member

    May 8, 2006
    I am having trouble in establishing a load for my AR-15. I keep having over pressure signs in the primers, blowing some primers completely out of the case at times. What is the inside diameter of NEW brass primer pockets? Can someone measure the inside diameter of NEW brass and give me the dimension? I measure anywhere from .174 to .176 on my brass. I think the .176 is too large since the primers (CCI 400) are measuring .175 in diameter.

    I collect brass from the range. We have a naval air station near by and the navy team shoots mil brass. I use the super swage to ream the primer pockets out. Before reaming I measure anywhere from .173 to .1745. I guess I'm measuring the crimp. I swage the crimp out and measure .175. Those I think are OK. However I also collect brass (can't help it - I scrounge) and after depriming, measure the pockets and it's up to .1765 at times. These I have not swaged since there's no reason to. I think these are going to fit too loose. Am I correct in this assumption?

    This problem is driving me batty!:banghead:
  2. mc223

    mc223 Member

    Jun 18, 2006
    Just Down the Road
    Sounds like you need to recycle that brass and get some good stuff. The Navy must be pounding the crap outa that brass.
    Google the SAAMI website for dimensions. They are in there, you just gotta look for them.
    I measured a brand new Hornady case at .1715.
  3. stormspotter

    stormspotter Member

    Jun 11, 2004
    Primer diameter

    Go to radomski.us/njhp/cart_tech.htm

    There is some primer info there.
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