Case rim variances??

ghostinthewoods

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Apr 8, 2013
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Today i was loading some new norma brass for 7mm saum. New rifle, I've only loaded about 150 all new brass but I noticed some of them were tight in the shell holder so I measure the tight ones compared to the ones that fit like they should and their 5 thou bigger around the rim??? I've Only noticed them out of this one box. Is this a problem and could it affect accuracy???
 

predatornut

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I had the same issue with Lapua .308 (tight in shell holder) with my Lee hand primer. I got a new shell holder and all is good.
 

ghostinthewoods

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That thought crossed my mind but some fit and some don't. Havent noticed it with any of the other 100 brass i reloaded. Didn't know if it
would effect anything in the rifle as far as accuracy?
 

Supersubes

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  • Sep 6, 2006
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    I dont believe it would affect accuracy. The question is, do they fit in your bolt face wihout binding, and does the extractor grab them properly? Shoot them over a chrono and test accuracy.
     

    predatornut

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    That thought crossed my mind but some fit and some don't. Havent noticed it with any of the other 100 brass i reloaded. Didn't know if it
    would effect anything in the rifle as far as accuracy?

    That is exactly what happened with mine. Some fit fine and I would have to force others. For the price of a new shell holder you would at least eliminate it as a possibility.
     

    BurnOut

    DDOJSIOC
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    Nov 24, 2013
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    I noticed the same thing when playing with some .308 Win cases from various manufacturers. In my case, it wasn't the diameter or even thickness of the rim that was variable, it was the area immediately above the rim (shown as having a value of .4091" in the diagram linked below). I can't comment on any impact that variation may have had on accuracy, but I can say that it has not (at this time) caused any problems in regard to function (re: extraction, etc...).

    https://upload.wikimedia.org/wikiped...tridge_308.PNG