Action modifications for 7mm Dakota

Discussion in 'Gunsmithing' started by One_Duck_Limit, Sep 7, 2010.

  1. One_Duck_Limit

    One_Duck_Limit Well-Known Member

    Nov 5, 2008
    I'm in the process of building a 7mm ????????. The stock arrived a few weeks ago and the barrel is on order. The barrel was ordered with a 1:9 twist with the intentions of shooting Berger 180 VLD's. I keep going back and forth between 7mm STW and 7mm Dakota. I've read all I can find on both and performance appears to be equal. Right now I'm leaning toward the Dakota. I like the idea of a shorter, fat case. The action for the build was taken from a Remington 700 7mm Remington Mag. I've read in varios places that the bolt must be modified and the feed rail may have to opened a bit. Can someone explain what modification are needed to the bolt? And, how much feed rail must be removed? I'm the type that I want to know what's being done to my gun when I take it in for work.
  2. Kevin Cram

    Kevin Cram Well-Known Member

    Mar 9, 2004
    The velocity difference between the 7 STW and 7 Dakota are almost the same. You should be able to push a 180g bullet between 3000 - 3200 out of a 28" barrel. I prefer the 7 Dakota as it headspaces off the shoulder rather than a belt. The only down side is the brass. Your stuck with Dakota brass which is a little pricey, but good quality. I have heard of a few guys who have necked down 338 Ultra Mag brass down to make 7 Dakota brass. From your Remington 700 7 Mag I would suggest getting a sako extractor installed. The Dakota brass is based off the 404 Jeffries case and it has a .545" case head rather than the .535" magnum case head. The factory extractor grove isn't quite cut deep enough and if you tried to close the bolt on a case with the factory extractor you will chew the brass off the rim. With the sako extractor it just simply snaps over easily. The feed rails will need to be opened up slightly about .030" - .040" from the 7 Mag to accept the Dakota case too.