Help, excessive headspace question

Discussion in 'Reloading' started by Tennessee Tater, Sep 16, 2013.

  1. Tennessee Tater

    Tennessee Tater Well-Known Member

    Messages:
    84
    Joined:
    Sep 24, 2012
    Hi all, I have a question regarding max headspace. I purchased a factory 338 RUM barrel, screwed it on with a new PTG .186 recoil lug, and rented a set of PTG headspace gages form 4d reamer rentals. The bolt will close on the no-go gage, but will not close if I add a piece of .002 feeler gage onto the back of the no-go gage. I measured the go gage with a Hornady headspace gage, then the no-go gage. There is .004 difference between them.

    The Hornady gage doesn't measure at the true datum line, the go gage measures 2.3750, the no-go is 2.3790

    The SAAMI chamber drawing for it shows headspace is 2.3490 min to 2.3590 max.
    I don't think the go gage is at min chamber spec.
    I primed a piece of brass, chambered it and fired it. The primer detonated & it looks like the firing pin hits the primer hard. It is deeply dented.

    My buddy says to strap it down in a lead sled and pull the string (I know, doesn't say much for the company I keep, & it's not his rifle that may come apart).

    Any ideas other than setting it back?

    Thanks
     

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  2. MagnumManiac

    MagnumManiac Well-Known Member

    Messages:
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    Joined:
    Feb 25, 2008
    If I read this correctly, the bolt should NOT close on a no-go gauge, that's what it's intended to do, tell you the headspace is too long.
    What it measures in some gauge that's used for measuring fired/unfired cases is irrelevant, if again I read this correctly, I'm unsure as to what you measured.

    The simple answer is if the bolt closes on the no-go gauge, then the headspace is dangerously long and needs to be rectified BEFORE you fire any more ammunition in that rifle, setting the barrel back by trimming the barrel shoulder is probably the only way to rectify this and get the headspace correct. I would try to get it at it'minimum or .002" above min spec for good case life.

    Cheers.
    gun)
     

  3. Tennessee Tater

    Tennessee Tater Well-Known Member

    Messages:
    84
    Joined:
    Sep 24, 2012
    Thanks, I already have the rifle in the truck ready to go to the smith.