Go / No go gauge???

Discussion in 'Gunsmithing' started by kbb468, Oct 2, 2007.

  1. kbb468

    kbb468 Well-Known Member

    Nov 1, 2005
    I built a 458 win mag on a Savage action and used a case to set up the headspace off the belt. I inserted the case with the barrel loose and then closed the bolt. I then tighten the barrel by hand until it came to a stop and wouldn't turn any more unless I applied more force. Next I locked the barrel down with the barrel nut which pulled the barrel back some creating my headspace.

    So now I am confused because if I add a piece of reciept paper to the case head the bolt will not close without additional force. However I ordered go, no go, and field gauges and the bolt will not close on the field gauge, the no go gauge or the go gauge.

    I thought that was wierd and something had to be wrong so I call foster to double check. I got out my dial caliper and checked the dimension of the gauges with the guy on the phone and it all checked out. The brass I used for the set up was A-Square. So now I order 400 pieces of Winchester brass and guess what, ........The bolt will also close on the win. brass. The foster representative said everything should be fine.

    Has anyone else experienced this before and should I be worried at some point?

  2. J E Custom

    J E Custom Well-Known Member

    Jul 29, 2004

    The go gauge is the one to use.It is the S.A.A.M.I spec for the chamber.

    I use the go gauge with shim stock .001'' thick to set head space.

    I ream the chamber .001 to .002'' deep then when I make up the
    barrel It ends up around .001'' or less.

    To verify I place 1 small round shim on the bolt face and close
    it on the go gauge.NOTE! Do not force the bolt closed!!!.

    If it does close then I go to a .002'' shim and try again, If I did my part
    it should not close. On belted cases I try for less than .001'' headspace.

    On semi autos I go for .003'' headspace for better functioning.

    I have found that some factory ammo will go even if the go gauge will not
    so dont use the factory ammo as a go gauge.Unless you use small base
    dies you will never get your reloads as small as the factory stuff. "Plus
    when you test the ammo for fit be sure and remove the fireing pin"
    to prevent having your whole day ruined.

    The no go gauge tells you when you have to much head space.

    I hope this helped
    Last edited: Oct 2, 2007

  3. specweldtom

    specweldtom Well-Known Member

    Jun 7, 2004
    Kbb; you're ok from a safety standpoint if the bolt won't close on the go-gage, but will close on factory brass. I have checked chambers that would not close on a go-gage, but would on factory brass. On a .458 Win Mag, I would go about .002"-.003" over the go gage. The belted cartridges are very hard to close (and may not), if the belt on the cartridge makes up on the chamber headspace face too early. Not good on a dangerous game rifle where you really want a round to chamber smoothly every time.

    Just my opinion, Tom
    Last edited: Aug 20, 2008