Resizing cases when loading for AR

Alabama556

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  • May 15, 2008
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    Birmingham, AL
    I have been reloading for over 20 years for bolt action rifles but just started loading for my AR a few weeks ago when I finally built a 300 blackout. I have loaded for 300 whisper with no problems for a long time but it is for a custom Remington 700.

    Typicality, I would set the sizing die to where it just bumped the shoulder for bolt guns.

    My setup is noveske 11.5 300 blackout barrel with pistol length gas system. Brand new Colt m16 bolt. The lower is a factory colt 11.5 setup.

    The brass I have is cut down from 5.56 cases and has never been fired. It will not fit in my noveske chamber when resized with my bolt action die.

    The resized fired brass from my bolt gun won’t fit in my noveske. (bolt gun is a 300 whisper and was built before 300 blackout was commercially availible).

    I set my resizing die all the way down and it resized almost the entire case. These fit and function but am I resizing the brass too much?

    I have 2 sets of dies so I can easily set one for the bolt action and 1 for the AR.

    Thank you.
     

    spife7980

    Luchador
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    Feb 10, 2017
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    Central TX
    I don’t see any measurements. How could we possibly identify the issue if you don’t have measurements?
     

    Alabama556

    Sergeant
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    Minuteman
  • May 15, 2008
    519
    82
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    Birmingham, AL
    OAL with 208 grain amax is 2.250
    Case length is 1.355

    If I turn the resizing die all the way down, the cases will fit.
     

    918v

    It’s not the primer!
    Full Member
    Minuteman
    Jul 15, 2007
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    Miserable CA
    We need more measurements. The case could be binding in the chamber at the neck, the shoulder, the body…
     

    spife7980

    Luchador
    Full Member
    Minuteman
    Feb 10, 2017
    11,628
    12,103
    Central TX
    OAL with 208 grain amax is 2.250
    Case length is 1.355

    If I turn the resizing die all the way down, the cases will fit.
    So you have no measurements.
    Take some real measurements.
    Example:
    78A6239B-129A-4F68-82A6-461EDE33D169.jpeg
     

    Doom

    Balding Eagle
    Full Member
    Minuteman
    Mar 24, 2013
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    South of the Mason Dixon Line.
    The problem you describe is typical of brass shot in one gun then sized for another. Usually the base of the cartridge is the issue and is usually solved by turning the die down or using a small base die. The only problem with turning the die down is you may end up with excessive headspace.
     
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