Quantcast
  1. Sign up now and join over 35,000 northwest gun owners. It's quick, easy, and 100% free!

Headspace guages

Discussion in 'Maintenance & Gunsmithing' started by iusmc2002, May 20, 2013.

  1. iusmc2002

    iusmc2002 Colville, WA Active Member

    Messages:
    577
    Likes Received:
    207
    Are the headspace gauges for a 7mm Rem Mag and a 300 Win Mag interchangeable? I also was wondering if the 30-06 and 338-06 gauges were interchangeable?
     
  2. nwbobber

    nwbobber Longview, Wa. Active Member

    Messages:
    206
    Likes Received:
    93
    No. The case dimensions of 7mag and 300 are quite different. The 06 guages might be of some use if you had the bigger one, but the 338 neck won't fit in a .308 hole.
     
  3. MountainBear

    MountainBear Sweet Home, OR Well-Known Member

    Messages:
    3,650
    Likes Received:
    2,374
    Actually, both the 7mm and .300 use the belted magnum headspace guage. And since the headspace guage doesn't go into to barrel (just the chamber, past the datum point), I believe the .338-06 and .30-06 should both work on the .30-06 guage, but I am not 100% sure if the datum point on the shoulder is moved when the .30-06 is necked out to accommodate the .338 caliber bullet.

    Forster Headspace No-Go Gage 30-06 Springfield 25-06 Remington 270

    BELTED MAGNUM CARTRIDGE HEADSPACE GAUGES | Brownells

    You are correct that the chambers are significantly different, but the chamber dimensions are less important that the location and dimension of the datum point. The datum point is the point where headspace is measured and varies based on the cartridge. On a .30-30, it headspaces off the rim. On a belted magum, generally on the belt. On a rimless cartridge, its generally a point roughly midway on the shoulder.
     
    Tigershark and (deleted member) like this.
  4. Silver Hand

    Silver Hand Southern Oregon Coast Well-Known Member

    Messages:
    871
    Likes Received:
    330
    MountainBear is correct when indicating the .300 win mag and the 7MM Rem Mag head space off the belt. I believe a common measurement is .220 in and .223 in for the .300 Mag.
    Silver Hand
     
    Tigershark and (deleted member) like this.
  5. Straight Shooter

    Straight Shooter North Bend OR Active Member

    Messages:
    206
    Likes Received:
    33
  6. nwbobber

    nwbobber Longview, Wa. Active Member

    Messages:
    206
    Likes Received:
    93
    Of course. I was thinking case gauge. Doh.


    .

    .