Enlarging Win M70 Mag box?

Discussion in 'Gunsmithing' started by elmerdeer, Sep 9, 2010.

  1. elmerdeer

    elmerdeer Well-Known Member

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    Hi guys I have a semi custom win model 70 in 280 converted to a 280AI, and I would like to be able to seat my Berger 168 vld's to touch the lands. My mag box has a rear false wall that limits me to a COL of 3.380" and and if I remouve that false wal I gain an extra .200" of space. Now I know it is spot welded on there and I am sure it can be remouved but would the outcome be If i do this? Will my rounds feed properly? They do now.Will I have to do any other machining work to the the bolt stop? And would my mag follower need to be adjusted?
    Thanks
    Elme
     
  2. winmag

    winmag Well-Known Member

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    Im not sure of the overall outcome, but I can help a bit.
    The bolt should stop usually flush with the mag box spacer plug. Once the plug is removed your bullets will be able to slide backwards past where the bolt will be able to pick them up. If its just a couple thousandths that you, need your better off ''shaving the spacer''.
    The mag follower is easily adjusted by slightly bending the ''z-metal'' for tension, however, when given too much room to ''wiggle'' its prone to get bound up.

    Depending on your skills, Id have a quality gun smith look at it, and see if you could extend the magazine on the front instead of the back, and hone the feed ramp.

    The other way to go would be to shorten the throat of the barrel, or shoot different bullets, but thats not what you asked.
    Sorry I couldnt be of more help. Maybe some others will chime in with a better idea
     

  3. Kevin Cram

    Kevin Cram <b>SPONSOR</b>

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    I would recommend installing a Wyatts extended mag box. You will need to open up the mag box cut out in the action and shorten the bolt stop a little. If it's a pre-64 you will need to shorten the ejector blade as well. If you have a mill it's not too bad of a job or give me a shout I'd be happy to install one for you.
     
  4. BigUglyMan

    BigUglyMan Well-Known Member

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    I bought a factory Winchester H&H length mag box and follower so that I could seat 210 Bergers out to the lands in my 300WM. You will have to modify the ejector so that the case on the LH side of the mag can rise high enough to be caught by the bolt. Also there will likely be some minor work needed to the rear of the feed rails to allow the round to rise and be contacted by the bolt to ensure feeding. As well there is a square bit on the action at the top of the mag box that had to be filed down. Worked like a charm.
     
  5. shortgrass

    shortgrass Well-Known Member

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    I think I'd order up a breech bolt stop for the Win. 70 in .300 Weatherby Mag. (Numrich Arms/Gun Parts Corp. $17.05) and install that on the action and see if the bolt will travel far enough to the rear to give what you would need. If it looked good, I'd remove the block in the magazine. You may need to do a little file work to the ejector and feed rails as noted above, but, I wouldn't just go to work on these unless the work was nesessary.
     
  6. elmerdeer

    elmerdeer Well-Known Member

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    So far seems to be feeding fine, but I might just order the shorter bolt stop and ejector.
    Thanks
    elmer
     
  7. shortgrass

    shortgrass Well-Known Member

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    If you're up to it, you may be able to shorten the existing bolt stop. You don't need a mill, a Nicholson 10" mill bastard file will work just fine, sometimes slower is better. I took a quick look at post'64 .25-06 yesterday, didn't do any measuring, but if your rifle was a job in my shop thats where I would start. All that bolt nose needs to do is clear the back of the mag box enough to pick-up the next round. Have you checked your proposed O.A.L. to be sure it will fit in the box with the block removed?
     
    Last edited: Sep 11, 2010
  8. elmerdeer

    elmerdeer Well-Known Member

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    From cycling plenty of rounds through it yesterday I did notice that ther is a small problem extracting, it seems that the extractor blade needs to be shortened abit for the shell to be able to come up to where the bolt will pick it up. Now as far as the bolt stop that seems ok but I will be checking it properly, as I have ordered the bolt stop and extractor blade for the 375H&H, 300 weatherby, so when they arrive i will install them and see how that functions. My bullets fit just fine in the mag and touching the lands with about .100" left to spare.
    Thank you
    Elmer