CRF Montana or Winchester model 70 in RUM?

Discussion in 'Gunsmithing' started by nw07heavy, Mar 27, 2015.

  1. nw07heavy

    nw07heavy Member

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    Hello all, I was thinking of converting my CRF Montana Rifle in .416 Rem Mag to .416-375 RUM. I understand the chamber reaming is easy and inexpensive to convert to a .416-375 RUM, but I was wondering about any issues with the magazine feed rails as to the dependability of a CRF action feeding the wider rebated rim case RUM case in lieu of the standard belted magnum case. As far as why I wish to convert, it is just to use a nice easy to reload wildcat for fun. Any information would be appreciated.
     
  2. Punisher

    Punisher Well-Known Member

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    The CRF action has no problem feeding wid cases. As for catching the rim, you need a new extractor. You will have to buy one in the white and file it yourself. The factory one "might" work, but won't be perfect. Look at all these WSM and WSSM cartridges with no issues.
     
  3. nw07heavy

    nw07heavy Member

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    Thank you very much for this information. I will address this with my gunsmith. Even though the rifle properly cycled all RUM rounds from the magazine I will make certain of the exact fit for the extractor claw.
     
  4. Punisher

    Punisher Well-Known Member

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    The extractor claw is an often overlooked detail. The smith should be able to figure that out, but you can test for problems by dropping a shell on the follower and single loading it. If the claw has problems slipping around the shell to extract it, that is when it needs to be filed down.

    Crpfs is the perfected version of crf. A true crf cannot be single loaded unless the shell is in the magazine. I know exactly how much of a pain it is to time the extractor slot and get the cone right, but they make a nice rifle when you're done.
     
  5. nw07heavy

    nw07heavy Member

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    Am I correct in understanding that the claw thickness, on the bore axis, if too thick, will preclude the claw from moving far enough out (blocked by the action itself) and around the cartridge rim in order to extract it with the backward pull? Thinning of the extractor then, will be to remove metal on the outside edge (opposite from the cartridge side), is this correct? I just want to be clear on this, and thanks much.
     
  6. Punisher

    Punisher Well-Known Member

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    No, it's not the thickness of the claw, it is the "S" shape and the bevel of the claw. If you look at a factory new claw, it is ground so it slides around the rim of the case.

    I will try to post a photo later.
     
  7. nw07heavy

    nw07heavy Member

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    Thanks for the clarification. I appreciate it.