378 Bolt face options

Discussion in 'Long Range Hunting & Shooting' started by HuntnID, Feb 8, 2011.

  1. HuntnID

    HuntnID Well-Known Member

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    Okay. So I have found a custom 30-378 Mark V for a price that is hard to turn down. I had the intentions of taking rebarreling a Mark V into a 338 Edge but I understand that the bolt face is bigger than the standard magnum boltface. My intentions are to shoot the 30-378 for as long as I can and once the barrel goes ka-put I could rebarrel into a 338 caliber.

    There isn't a way to rebarrel into a standard magnum bolt face right?

    So here is my question what caliber options do I have? I know the 338 lapua is an option, the 338-378 seems to have poor barrel life. Any other options? Lapua improved maybe? What are the Allen Mags based off of? I haven't seen much info for them. Thanks, Ron
     
  2. mphstigerfan

    mphstigerfan Well-Known Member

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    The Allen mag is 408 Chey tac and the Allen express is 338 lapua brass modified if I'm not mistaken I would think barrel life on a 338-378 would be drastically better than the 30-378 though I have little experience with the weatherby
     
  3. screech

    screech Well-Known Member

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    problem with weatherby is brass is too soft, I believe the old 7mm allen was based off a 338 lapua necked down to 7mm. If it was me Id do a 338 lapua or a 300 lapua
     
  4. RDM416

    RDM416 Well-Known Member

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    HuntnID,

    I think you are going to be stuck with the "378" family from WBY. The Lapua, if I am not mistaken requires a larger boltface than the WBY. Don't know for sure if the WBY can be opened up enough. Maybe one of the smiths on the site will weigh in and answer that one for sure.

    In 338 cal, that leaves the obvious choice of 338/378 or it's improved variations such as the 338 Kubla Khan and others.

    Barrel life is not that bad. I just a new barrel put on one of my Kahn's. It had 1500+ rounds down the tube and was still shooting fine. It is just a long process to get the barrel ordered, then get on Kirby's schedule to get it done that I went ahead with the new barrel even though I could have gotten a little more use out of the old one.

    Brass is soft, and I would rather be shooting Lapua brass for sure. However, the brass is good brass and if you don't push it too hard and loosen the primer pockets you can get 10 loadings. Start out with a 100 rounds of new brass, take care of it and you can get 1000 rounds down range before you have to worry about brass again.

    Final plug..... the 338/378 is considerably faster than the Edge or Lapua and is still 50 to 100 fps faster than the Lapua improved. Not the only consideration, but one worth knowing.
     
  5. J E Custom

    J E Custom Well-Known Member

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    For a hunting rifle barrel life is not that big of a deal because of the total rounds fired over
    many years. And any of the big 30 or 338 mags are tough on barrels compared to a 308 win
    class of cartridge.

    Weatherby brass is made by Norma and with good loading techniques can last a long time.

    The 338/378 will out do most of the 338s with big bullets and this would be the obvious choice
    for the rifle. (No mod required).

    The next choice in my opinion would be the 337 Lapua Improved . It is not as powerful as
    the 338/378 but is a fine performer and has very good brass.

    The 338 Lapua has a head diameter of .588 compared to a 338/378 Weatherbys .379.
    The bolt face can be opened up very easy (.009) and the Same extractor will work with
    with the Lapua case.

    The flat top follower and center feed in the 338/378 works perfect for the Lapua also.

    All of the rum based cases have smaller bolt faces and need to be modified or replaced with a standard Mag bolt face (.534 Dia.).

    J E CUSTOM
     
  6. Good

    Good Well-Known Member

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    The 338 Norma Mag also has the Lapua bolt face so there's another option. It is good starting with the big bolt face as you already have a large cartridge capability concerning mag feeding, etc. I would stick with the 338-378 if I were you as it performs well and you will not need to mess with the bolt at all, just re-barrel, and you can purchase the brass easily, although pricy.

    Even though I'd like to have a Lapua improved or Allen Mag, I don't like the idea of having to modify brass and all the work that that entails. I'd rather work up loads and shoot, but you may not mind all that. You can also purchase the Norma Mag brass without having to modify it.

    Another option out there is straight 378. Now that high BC 375 caliber bullets are out there and becoming more prevalent, this option may be attractive to some...
     
  7. HuntnID

    HuntnID Well-Known Member

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    Thanks guys. I guess I just had heard some people talk down on the 338-378 so I just had to get more information on it. I may go with that although a 338 Allen Xpress would be intriguing. So this cartridge is 150 fps faster than a Lapua correct?
     
  8. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    Whoever told you the 338-378 wby is hard on barrels is wrong. I doubt through normal shooting you will wear one out if you take care of it. I have seven of them and my favorite one has over 1500 rounds through it with good accuracy. The improved 338-378 is hard to beat performance wise. The 338 Excalibur will fit on that bolt face and is about the most powder capacity you can get if you want the most velocity off that bolt face. The edge or 338-300 RUM you mentioned is a good choice for a standard mag bolt face but since you have a top action you don't want to go backward and lose up to 300 fps advantage the 338-378 wby variations can get you. Basically the 338's off the RUM case average about 2800 fps with a 300 grain bullet and with the imp 338-378 and excalibur you can easily hit 3100 fps and more with a 300 grain bullet. Quite a difference when your shooting long range. They are all accurate. The improved lapuas can get you well into the 2900's and will fit on your bolt face. My accuracy load in my favorite 338-378 wby with a 300 grain bullet gets 3064 fps out of a 28" barrel.
     
  9. Good

    Good Well-Known Member

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    I just want one!!!:)
     
  10. lazylabs

    lazylabs Well-Known Member

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    If you get a 338/378 have a detailed conversation with the smith about the reamer specs. There are some match reamer setups that eliminate the free bore and you can throat it for the 300's or..... stay factory specs to shoot factory ammo. I have a more normal throat setup in mine and like shooting it with 30" barrel you get some good velocity.
     
  11. nitrousmudbogger

    nitrousmudbogger Well-Known Member

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    338-378 is tough to beat. Put a long barrel on it or it will be a flame thrower and not utilize the powder burn. I did a lot in the early nineties with a 338-378 Kubli-Kahn which is a 338-378 Wby with a sharper shoulder. Now that some better bc bullets are coming out for 338 thats the way i'd go. Easy to get brass, reload, etc.
    Lapua is always a good choice if you dont want a belted mag
     
  12. cswegener

    cswegener New Member

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    I was under the impression that the 378 and the lapua can interchange bolt faces. Is that the case or no? I'm looking at getting a action and bolt to make 338-378 and was told the lapua bolt face would work without any alterations. Just wanting some advice prior to buying. Thanks
     
  13. dkhunt14

    dkhunt14 Well-Known Member

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    I can go over 3100 with a 300 Berger in my Lapua Improved and no pressure. The brass of the Lapua is way better and lasts. You could always get Hornady to make a Hydro die to form cases. No rounds through the gun and almost perfect formed cases. My gun shoots good forming and I just put the bullet hard in the lands and use a lot of neck tension. Matt
     
  14. Tikkamike

    Tikkamike Well-Known Member

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    My vote goes to making it a 378 weatherby, I know you want a 338, but the amount of badassery that comes with a 378wby, I wouldnt be able to sleep tonight if I didnt recommend it. CE and a couple others make some high BC bullets,, it would be an elk destroyer.