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  1. #1
    Join Date
    Jan 2006
    Location
    Rossendale, Lancashire
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    1,360

    Primer Pocket Depth

    Evening chaps, I've had a few issues lately with with primer/primer pocket dimensions so apologies in advance for all the questions!

    Ok, so I'll start from the beginning. I primed 100 Norma .223 (once fired) cases with CCI small rifle primers, but noticed the majority of the primers sat proud of the case head by anything from .001"-.005". I chambered a few primed cases in my rifle (firing pin removed) and got a little witness mark where the bolt face closed on the primer, and the extra pressure could be felt when closing the bolt. Not happy with this so knocked all the primers out.

    Looked up this page online for SAAMI primer pocket dimensions:

    https://ballistictools.com/articles/...d-diameter.php

    Measured the depths of my primer pockets which were all between .118"-.119", so they were in tolerance, but on the shallower end. Measured height of 100 primers and got sizes from .119"-.124". Still within tolerance but no wonder they won't sit flush in my cases, right?...

    ...So, I buy a primer pocket uniforming tool. This cuts the pockets out to a rather disappointing .120" deep. So with my primer pockets "uniformed" the primers still have no chance of sitting below flush.

    So I'm left thinking:

    1. the primer pocket uniformer should surely be cutting deeper, towards the top end of the limit (.123")?
    2. CCI are inconsistent and cr@p and I need to look for a new brand of primer that are shorter?

    Here's the bit that makes no sense to me: The max tolerance for the primer pocket depth is .123" but the max primer height is .126"?? Who the hell came up with those tolerances?!? So even with the pocket cut to full depth a primer at max height tolerance is impossible to sit flush.

    At the moment I've no chance of success with the setup I've got so don't know whether to return the primer pocket uniformer tool or try different primers which average out below .120" (hopefully these exist).

    I've got a load of brand new Lapua brass and all those primer pockets measured around .119" too, so the batch of CCI primers I have wouldn't fit those either.

    Thanks for taking the time to read all that, hopefully it makes sense. Any advice much appreciated!

    Cheers
    Greg

  2. #2
    Join Date
    Jan 2012
    Location
    Leicester
    Posts
    1,321
    if your primer uniforming tool can not be adjusted that is poor ,the k&m one can and i would recomend k&m gear highly .but i also rate cci primers.

  3. #3
    Join Date
    Jun 2006
    Location
    Newport, South Wales.
    Posts
    1,093

    Thumbs up Primer pocket.

    Hello,

    I wish that I could provide the answer to your problem.

    It's very strange, I have loaded many, many thousands of rounds using CCI primers, 100% for 0.223", a RCBS primer pocket tool and a very old Lee primer "loader", and I have never had a problem like yours.

    Perhaps try a new pocket cleaner and another batch of CCI primers.

    When you are loading the primer do you find it unduly difficult to insert the primer, pressure wise?

    Good luck with solving the problem.
    6.5 55 SWEDE.223 HOWA VARMINT NIKON 8X32X50 -.22LR CZ STYLE-16" .17 HMR CZ AMERICAN-16" SIMMONS AETEC-12G BERETTA A.302,AYA NO 4,BAIKAL O&U

  4. #4
    Join Date
    Jan 2006
    Location
    Rossendale, Lancashire
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    1,360
    Quote Originally Posted by zx10mike View Post
    if your primer uniforming tool can not be adjusted that is poor ,the k&m one can and i would recomend k&m gear highly .but i also rate cci primers.
    Thanks for the reply. I got the Lyman tool. It isn't adjustable but I deliberately chose a preset one. The words "adjustable" and "uniform" seemed a bit of a contradiction to me. I'm not saying it was the best choice (evidently it wasn't!) but I'll look at the K&M tool, thanks for the recommendation.

    Quote Originally Posted by CROWMAN View Post
    Hello,

    I wish that I could provide the answer to your problem.

    It's very strange, I have loaded many, many thousands of rounds using CCI primers, 100% for 0.223", a RCBS primer pocket tool and a very old Lee primer "loader", and I have never had a problem like yours.

    Perhaps try a new pocket cleaner and another batch of CCI primers.

    When you are loading the primer do you find it unduly difficult to insert the primer, pressure wise?

    Good luck with solving the problem.
    Thanks for the reply. The primers aren't difficult to seat, there's a nice amount of resistance felt when they push in and go to a solid positive stop. Perhaps the primers are a bad batch, there's a lot of variation in them and they're all on the long side. This weekend I'll get some more CCI and try another brand like Federal too.

    I refuse to believe that primer pockets on brand new Lapua brass should even need to be cut, the primers should be correctly sized so they sit below flush.

    Cheers
    Greg

  5. #5
    Join Date
    Jun 2006
    Location
    Newport, South Wales.
    Posts
    1,093

    Primer pocket

    Hello Greg,

    Yes, I believe you are absolutely correct in believing that new Lapua brass should not have to be pocket cut.

    It's a good sign that you have a small amount of resistance when loading the primer, that sounds good.

    If it's new brass as you say, then it would seem to lead to the primers?

    What primer tool are you using? LEE, RCBS ? But again as long as you are using enough pressure to insert the primer as far as it will go, then it would seem to be the primers? Again though, I have never had one instance in many many years of faulty CCI primers.

    I wish I could be of more help, it's so annoying! I know from experience that these reloading problems can either intrigue you or drive you mad !

    Good luck in solving the problem.
    6.5 55 SWEDE.223 HOWA VARMINT NIKON 8X32X50 -.22LR CZ STYLE-16" .17 HMR CZ AMERICAN-16" SIMMONS AETEC-12G BERETTA A.302,AYA NO 4,BAIKAL O&U

  6. #6
    Join Date
    Jul 2014
    Location
    Watford
    Posts
    8,379
    If you are unsure of your primer pocket - one of these gauges can come in handy. I suppose you can use a calliper and measure but if you have acquired brass of an unknown provenance, this can check the pockets in fairly short order.

    https://www.sinclairintl.com/reloadi...prod71030.aspx

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