Rechamber a Rem 700 300 WSM to 7mm WSM?

Discussion in 'Gunsmithing' started by Shootin4fun, Jul 4, 2012.

  1. Shootin4fun

    Shootin4fun Well-Known Member

    Messages:
    331
    Joined:
    Dec 3, 2010
    I am considering building up a 7mm WSM on a Rem 700 platform. Can I take a Rem 700 rifle, and rechamber it from 300 WSM to 7mm WSM by getting a custom barrel and having a gunsmith rechamber & mount it? I saw Rem 700 actions for sale, but it said specifically, "Rem 700 SA 300 mag". I would have thought that they could be chambered for any WSM.
     
  2. Daveinjax

    Daveinjax Well-Known Member

    Messages:
    504
    Joined:
    May 21, 2012
    Yes you can.:)
     

  3. grit

    grit Well-Known Member

    Messages:
    1,375
    Joined:
    Mar 23, 2005
    300 WSM just tells you what it was / is so you know what it's readily suitable for. A 7 WSM would be a simple switch. I would choose a long action for the WSM's. At least, use a Wyatts extended mag box. The RSAUM's are a better fit for the short actions.
     
  4. Daveinjax

    Daveinjax Well-Known Member

    Messages:
    504
    Joined:
    May 21, 2012
    I second the wyatt magazine box. I'm using it on two of my 700's. You just have to mill a little bit ( @ 1/8 inch.) From the back of the magazine inlet where the ADL trigger mount screw would go.
     
  5. Shootin4fun

    Shootin4fun Well-Known Member

    Messages:
    331
    Joined:
    Dec 3, 2010
    Wow, I don't understand how this works at all then...I would think a SA mag action would be the best fit for a SA cartridge. Why would a LA action be better?

    I would think the long action chamber would be too long for a WSM cartridge. doesn't that leave a lot of play of the bolt behind the rear of the cartridge, or do you put a stop in at the appropriate length?

    Also, doesn't that defeat one of the advantages of a short action, that being a shorter bolt throw?

    Thanks for your advice!
     
  6. geargrinder

    geargrinder Well-Known Member

    Messages:
    1,972
    Joined:
    Nov 6, 2006
    Take a look at the length of the 7mm bullets you will be shooting. The one's for long range shooting are quite long. The 180g SMK, VLD, and Hybrids are quite long.

    If you have a short action mag box, you are limited in the OAL. Meaning you'll have to stuff more of the bullet into the case. More bullet in the case is less powder available. Less powder is less fps.

    That is the benefit of the long action. You aren't limited by OAL by the action, only by the throat of the chambering.
     
  7. grit

    grit Well-Known Member

    Messages:
    1,375
    Joined:
    Mar 23, 2005
    I didn't mean to confuse you. I'm strictly speaking about optimizing the cartridge performance for long range use. Many cartridges are cramped by the magazine when using the long VLD bullets we use for long range shooting. Literally, most cartridges. The Winchester short mags were developed for Winchesters short action, which is longer then Remingtons. This makes them particularly cramped in a Remington short action.

    If you seat a 180 Berger to the neck shoulder junction of a 7WSM it simply will not feed through a short action. I regularly build WSM's on long actions to utilize the case capacity and seat the bullets where they belong.

    The Remington short action ultra mags were designed for Remingtons (shorter) short action. They are still cramped. But, an extended magazine box will allow you to run VLD's seated where they belong.
     
  8. Daveinjax

    Daveinjax Well-Known Member

    Messages:
    504
    Joined:
    May 21, 2012
    As this is going to be a custom barrel you can have the throat cut to match the bullet and magazine lenght if you want to use a short action for weight savings and compactness. You need to talk to a smith about what you want and what they can do for you. If this is going to be a carry around all day hunting rig you may want to stick to a short action with an extended magazine box and a light barrel. If you are not going to carry ot around much then a long action with a long heavy barrel to get all you can get out of the round would be in order. Compromises have to be made , thats why you need a safe full of rifles ! :)
     
  9. Shootin4fun

    Shootin4fun Well-Known Member

    Messages:
    331
    Joined:
    Dec 3, 2010
    That's what I keep telling my wife! :D
     
  10. sj-pratt

    sj-pratt Official LRH Sponsor

    Messages:
    125
    Joined:
    Dec 7, 2006
    I have done a number of 7MM WSM in short act6ions throated for 180 bergers and have found that with the Wyatt's Box you can still run them at 3000 fps and it has proved to be a very good hunting round at that speed.
     
  11. J E Custom

    J E Custom Well-Known Member

    Messages:
    7,307
    Joined:
    Jul 29, 2004

    The long action only allows you to seat bullets way out. The short action works fine for the 7 WSM
    and if you want to keep it simple, chamber the 7 wsm with a SAMMI reamer and load to magazine
    length and factory ammo will shoot fine and reloads can be made to shoot well @ magazine length.

    I have built quite a few on Mod 7 actions for the same reason (To keep the rifle short) and they
    all shoot under 1/2MOA. I have built several 325 WSMs and a couple of 338 RCMs on the SA and
    have been very pleased with there performance also.

    If you want to load heavy bullets (170+) then the long action should be considered. But for 120s
    to 160s the short action works well.

    Just my opinion

    J E CUSTOM