7mm Rem Mag to .280AI

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Janno05, Apr 18, 2013.

  1. Janno05

    Janno05 Member

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    I apologize if this is a stupid question, but is it possible to rechamber a Winchester 70 in 7mm Rem mag to a .280 AI? If it required a rebarrel, how difficult would it be to switch to a 30-06? I finally found a LH Stainless Model 70 but have no desire to own a belted magnum. Thank you!
     
  2. 429421Cowboy

    429421Cowboy Well-Known Member

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    The only stupid question is one that doesn't get asked!

    I think it would be a bit more than you'd want to mess with, a simple rechamber would not be possible, it would require a new barrel, and the magnum boltface would not be compatable for a standard '06 size cartridge.
     

  3. wyoguide

    wyoguide Member

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    Don't think it would work. The '06 and 280 are "standard" cases .473 diameter, while the 7mm remag is a "magnum", or .532 diameter. In a crf action like the win, it'd be fairly easy to go from small to large, but large to small would require a different bolt. If a bolt could be obtained ($$), there is still the matter of the feed rails, which might not work correctly w/ the skinnier case.
     
  4. Janno05

    Janno05 Member

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    If that is the case, how is the 7mm Rem Mag? I really would prefer a 30-06, but I can't seem to find a LH Winchester to save my life, especially one in stainless. Is it worth it to hold out, or should I go for a Ruger or Remington? I really like the idea of CRF, but it might not be worth it.
     
  5. MudRunner2005

    MudRunner2005 Well-Known Member

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    7Mag is an awesome caliber. Been shooting them for 10-11 years now. I'm a 7mm nut. I have a 7mm-08, 7mm RemMag (x2), and a 7mmSTW, and fixing to build a .280 AI (which is also a 7mm bullet).

    Had a 3rd 7Mag, but it got stolen years ago, so I recently replaced it with an identical one.
     
  6. azsugarbear

    azsugarbear Well-Known Member

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    The 7mm Rem mag has about the same ballistics as the 30-06. Both can drive a 180 gr. bullet about 2800 fps. But the superior BC's of the 7mm bullets make the 7mm Rem Mag a much better candidate for some LR shooting. If memory serves me correctly, the cartridge does not headspace off the belt, so the belt on the case is more for show. If the rifle shoots, I would keep it.
     
  7. wyoguide

    wyoguide Member

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    Given a choice, I'd pick the 7mm rem mag over the '06 every time. Factory ammo is almost as plentiful, at least in the western states, if you are not a handloader. OTOH, a crf '06 makes a great donor to build something interesting on.......
     
  8. woods

    woods Well-Known Member

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    It will be a much easier rebarrel if you pick a caliber that is close to the .532" boltface you have. A couple that come to mind if you like the 7mm caliber would be the 7 WSM or the 7 SAUM. They are short action calibers but I have rebarreled a couple of 300 win mags to short action calibers and feeding has not been a problem.

    If you are not stuck on 7mm's then the list gets much longer for unbelted cases:

    300 RCM
    300 WSM
    338 RCM
    375 Ruger

    If your magazine is extra long then you can add the RUM's as unbelted cases with a .532" boltface.
     
  9. AZShooter

    AZShooter Well-Known Member

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    Point of information:

    A 7 rem mag headspaces with the belt. The go/no go gauge for a belted magnum is very short and is interchangeable for the entire family of H and H style cases and only measures the distance from case head to belt area.

    After the first firing the case can headspace on the shoulder.



    From Brownell's:

    Determine Correct Headspace

    With the exception of the .240 Weatherby Magnum, most belted, magnum cartridges are based on the .375 H&H Magnum case.

    Therefore, they all use the same headspace gauges

    The following is a partial listing of those cartridges which use the same Belted Magnum Headspace Gauges: .257 Weatherby Mag., 6.5 Rem. Mag., .264 Win. Mag., .270 Weatherby Mag., 7mm Rem. Mag., 7mm Weatherby Mag., 7mm STW, .300 H&H Mag., .300 Weatherby Mag., .300 Win. Mag., .30-.338 Win. Mag., .308 Norma Mag., 8mm Rem., .338 Win. Mag., .340 Weatherby Mag., .350 Rem. Mag., .358 Norma Mag., .375 H&H Mag., .416 Rem. Mag., .458 Win. Mag.

    BELTED MAGNUM CARTRIDGE HEADSPACE GAUGES | Brownells