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Thread: Headspace Question, USGI Pistols

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  1. #1
    Join Date
    17th September 2007
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    Headspace Question, USGI Pistols

    I was just wondering, is the max headspace allowed(.920 I believe) on 1911s
    a military spec or a more modern spec? I know that most of the Norincos
    have borderline headspace and they are supposed to be fairly good
    copies of an Ithaca I believe. Were most USGI pistols at the high end
    of headspace? Does anyone have any measurements on USGI pistols?

    Thanks
    Last edited by ron burgundy; 28th January 2010 at 17:27.


  2. #2
    Join Date
    25th September 2006
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    0.920" is the current maximum SAAMI headspace for 45 Auto/ACP guns, but I don't know if it has always been that.

    Ordnance blueprints I have (regardless of vintage, 1940 to 1990's) show 0.925" of maximum "breeching space" for Gov't Issue 1911's.

    Can't asnswer any of your other questions.

    Regardless
    When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. [Lord Kelvin]

  3. #3
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    17th September 2007
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    Thanks for the info.

  4. #4
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    1st June 2004
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    .920 is the upper end, but many guns will appear to go to battery on the N-GO gauge when the static dimension is less than that. When I get one that does, I compare the slide and frame relationship at the rear...with and without the gauge.
    If the slide stands a little further back with the gauge than when the chamber is empty...I know that it's not actually at the maximum allowable dimension.

    The .925 gauge is a field gauge that tells you without a doubt that the headspace is beyond allowable specs.

    I've seen a few NIB Norincos that would go to battery on the NO-GO gauge, with room for a .010 feeler gauge between the headspace gauge and the breechface...and the guns shot fine.
    Last edited by 1911Tuner; 28th January 2010 at 19:51.


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