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Thread: Headspace

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  1. #11
    Join Date
    16th July 2005
    Posts
    756
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    0
    It's very helpful, Tuner, as always.

    So no one should worry, this is NOT a real gun, just an example with minimum dimensions I made up to be sure I understood the various relationships involved with headspacing, and with the unsupported section of the chamber.

    Still, I see now why you frown on cutting the barrel so close to the limit. I thought about tolerance stacking, and slide-slap with the barrel lugs(part of firing-locked hs), but I confess I didn't think to consider wear, stretch, flex, and the like, nor about case web variance. Not to mention much used cases. It wouldn't take much to get into dangerous territory, NOT good.

    Is there a spec for chamber minimum supported length at the 6:00 position? There must be, but how the devil would you measure it? - about the only way I can think of is with casting alloy (Cerro Safe or such).

    Also, while you are very right to warn us never to rely on it, wouldn't the ammo manufacturers allow for some level of wear, out-of-spec barrels, max headspace, etc. in their case design?

    (Got another question about lug fitting, later on)

    Once again, priceless, and thank you.

  2. #12
    Join Date
    1st June 2004
    Location
    Lexington, North Carolina...or
    Posts
    11,260
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    Quote Originally Posted by gbw
    Is there a spec for chamber minimum supported length at the 6:00 position? There must be, but how the devil would you measure it?
    Yep...but I forget what that dimension is. You can figure it out with a right triangle and using the good ol' Pythagorean Theorum.

    Due to the low pressures generated by the .45 ACP...even the +p stuff...the head support leaves a little more wiggle room than with a cartridge like the .38 Super or the 9mm Luger.

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