REBARRELLING 338/378 WEATHERBY

Discussion in 'Long Range Hunting & Shooting' started by Down Under Hunter, May 28, 2007.

  1. Down Under Hunter

    Down Under Hunter Well-Known Member

    Messages:
    912
    Joined:
    May 10, 2007
    Sorry to ask so many questions guys ! /ubbthreads/images/graemlins/blush.gif /ubbthreads/images/graemlins/blush.gif This is the only place I get straight answers.
    If I was to buy a 338/378 accumark and rebarrelled it with a quality 30-32" tube what sort of velocities could I expect to get from 300 smk's. Would this be the most ecconomic 338/378 with a barrel length to maximise the round ? Would the factory mag have enough room for the big long high bc bullets.

    Thankyou all for your interest !
    /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/smile.gif
    cheers
     
  2. James Jones

    James Jones Well-Known Member

    Messages:
    2,854
    Joined:
    Jul 1, 2002
    I don't think that Weatherby and ecconomic need to be anywhere in the same conversation. That being said the 378 Case and its wildcats are the biggest kids on the block without stepping up to the real big cases like the chytac , so a longer barrel will give higher velocities with that case. Now I think that the 338 Lapua improved case would give realy close the same velocities with less powder and longer case life due to the ability to run higher pressure , and this round would be just barely overstepping the 338 Edge.

    so what it boils down to is what kind of budget do you have , are you willing to spend a pile of money for good quality brass thats only gonna last 3-4 firings with full house loads to get the absolute max powder (378) or would you settle for loosing a little velocity for a little bit cheaper brass that will last 10-12 firings?
    I think that their might be MAYBE 200fps velocity spread between the 338 Edge and 338-378Wby with the 300gr bullets and a 30" barrel. For economy sake I'd say that the 338Edge would be the way to go , you'll get longer barrel life , feed from a Rem 700 action and the brass is very available. the next step would be the 338Lapua improved , it'll feed from the Rem 700 and barrel life would be decient with velocity just a tick above the Edge and the brass is simply great but about $2 a case. Lastly would be the 338-378 Wby , it can be made to feed from the Rem 700 but I woulden't reccmend it , barrel life will be shorter , case life will be short though the cases are very good and the velocity will be the highest of the three due to the most powder capacity.

    So is the extra 200fps that you might get wourth the extra cost? I personaly don't think that any critters will notice.
     

  3. J E Custom

    J E Custom Well-Known Member

    Messages:
    7,307
    Joined:
    Jul 29, 2004
    Down Under

    James is dead on but you did say 3000fps and somewhere
    on this site a year or so ago I saw 3200 to3300fps with
    a 34" tube out of a 338/378 .

    As far as the mark 5 action compared to the REM the Mark 5
    magazine is about .100 longer (max OACL for rem is 3.700
    the Mark 5 is 3.800 .but with the weatherby freebore you can seat the 300 SMK way out and single load.

    And if you dont like the radius sholders there is a improved version with 30 or40o and about 4 grains
    more capacity.

    Brass is about $2.oo a peace and is made by norma.

    You can never have to much Horsepower but there is always
    a price .

    Good luck
    J E CUSTOM
     
  4. jwp475

    jwp475 Well-Known Member

    Messages:
    2,595
    Joined:
    Feb 4, 2005
    [ QUOTE ]
    Down Under

    James is dead on but you did say 3000fps and somewhere
    on this site a year or so ago I saw 3200 to3300fps with
    a 34" tube out of a 338/378 .

    Good luck
    J E CUSTOM

    [/ QUOTE ]

    That's very close to 338 Snipe Tac and AM territory. I would be rather skeptical of that claim....[​IMG]
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

    Messages:
    6,848
    Joined:
    Jun 12, 2004
    If you load a 338-378 Wby to 3200 fps in even a 36" barrel you will be depriming the case when you open the bolt.

    This is the performance range of the 338 Wildcats based on the 408 CT case. I have loaded for the 338 Kahn for alot of years and run that round hard, harder then it really should be at times and in a 34" barrel, if you break 3000 fps your doing good. If your getting near 3100 fps your buying new brass after the first shot.

    Just my experience. /ubbthreads/images/graemlins/grin.gif

    Kirby Allen(50)
     
  6. J E Custom

    J E Custom Well-Known Member

    Messages:
    7,307
    Joined:
    Jul 29, 2004
    Down Under

    I tried to find the post that claimed 3200 to 3300fps but
    gave up and as jwp475 said I was skeptical to because my
    experience was with 27 to 28" barrels at 2750 to 2800fps.

    But I guess its like gas mileage and long shots some people
    tend to stretch the distance.

    Sorry I quoted someone else,s post that could mislead you.

    And I appreciate JWP and Kirby speaking up THANKS GUYS

    J E CUSTOM