.338 RUM question

Discussion in 'Reloading' started by Topshot, Apr 19, 2010.

  1. Topshot

    Topshot Well-Known Member

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    OK boys,
    What velocity do you think is achievable from a .338 RUM with 250 grain bullets out of a 24.5 inch barrel?
    What load would you use?
     
  2. jbroadnax

    jbroadnax Well-Known Member

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    Don't know how much this helps but....Gunmaker just finished my 338 ultra. Rifle has 24" barrel. I am getting 3200fps with 225 Accubonds on top of 92grs of RL22.
     
  3. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    Somewhere in the 3000's and I would use a powder from Re 22 to 7828. I don't think you need to go slower than that with the short barrel. My winchester WMR would be perfect for it but I may be the only one left with this stuff. It was like gold to lapua and lapua imp. shooters until it all dried up. I bought up all I could find in the country and only have 100 or so pounds remaining. I can hit 3100 fps with my 26" barrel.
     
  4. Topshot

    Topshot Well-Known Member

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    Only 100 pounds or so? Man you must love your shooting.

    Is that 3100 fps with a 250 grain bullet?
    I see Remington factory loads are only listed at 2860 fps with a 26" barrel.
     
  5. Eaglet

    Eaglet Well-Known Member

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    Based on the above info; it can be projected to give us an idea.

    [​IMG]

    The projection was based on the above info. We need to keep that in mind.

    Long Time Long Ranger is pretty much right on!

    The little program uses one of the formulas in Mr. Bryan Litz's Book!

    This freely distributed application can be downloaded right here.

    http://pages.sbcglobal.net/jomoncada/Eaglet_Ballistic_Calcs/readme.zip
     
  6. Topshot

    Topshot Well-Known Member

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    Going on that information.
    If I reamed out my Sako .338 WM to .338 RUM I would get an extra 360 fps with the 250 grain bullet.

    This is a serious improvement with a 24.5 inch barrel.
     
  7. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    My 338 ultramag is a rem 700 26" barrel. I shoot the 225 accubond at 3264 fps with 99 grains of re-25. It is safe in my rifle and have about five firings on some brass right now. With the 250 and WMR my accuracy load hits 3080 fps. You can go well beyong the 338 win mag and in my opinion would be worth the trouble.
     
  8. MagnumManiac

    MagnumManiac Well-Known Member

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    Hey Topshot,
    I already answered your question over on AHN, what, you didn't believe me because of all those other dejections?
    I know my ----!

    2950fps-3000fps was my answer!

    Thanks.
     
  9. Topshot

    Topshot Well-Known Member

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    MagnumManiac,

    I believe you. If you say that is what you get then why would I not?

    But different rifles shoot different velocities and run at different pressure. Some rifles are faster than others even with the same barrel length.

    When I am going to spend plenty of cash on a rechamber job, I want to know that the money will not be wasted.

    I will try to get as much information as possible from a wide variety of people with experience. LRH has some real nice and experienced shooters and I value their opinion.

    Wouldn't you do the same thing????
    But then maybe you "know your own ----" and don't need to seek the opinion of others?
     
  10. woods

    woods Well-Known Member

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    Hey topshot

    I REBARRELED a 338 win mag into a 338RUM which is essentially the same as reaming your existing barrel out. I just got tired of pushing the 338 win mag hard to get any kind of velocity, lucky to get 2800 fps with a 225 gr bullet.

    There are a couple of things you need to consider and you may have already done so. One is that the 338RUM cases are longer and your magazine may be a limiting factor on OAL

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    Mine had a long detachable magazine (Beretta Mato) at 3.685" and most Sako's I have had or loaded for had long mags also at 3.730" so it may not be a problem. But, in order to fit in my magazine, I have to seat pretty deep at 3.600", which is actually the manual recommended OAL.

    The other thing is that I wanted to be able to seat close to the lands so I had the gunsmith ream the chamber so it did not have a long throat and I could actually seat close to the lands. In my chamber the distance to the lands is:

    225 TTSX - 3.628"
    225 AB - 3.620"
    225 IB (Interbond) - 3.580"

    This had a dramatic effect on chamber pressure and I can not load to book max and keep the primer pockets on my cases. When I first started out I loaded a string going up to the book max for 225 gr bullets up to the max of 98 grs of RL25. I got good accuracy

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    but my primer pockets were toast on those loads. I have heard the 338RUM Remington brass is soft so that may be part of the reason.

    Now I am down to 94 gr RL25 in order to keep my primer pockets and still getting good accuracy but velocity is down to 3050 to 3080 fps. That is just fine with me since all I wanted was to hit 3000 fps anyway.

    So if you have the barrel reamed out to 338RUM and you come to the decision about how long a throat you want, you may want to tell the gunsmith to ream to factory specs and put up with the jump. That way you can use manual loads and shoot factory ammo.
     
  11. Topshot

    Topshot Well-Known Member

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    WOODS

    Thanks for that, great shooting by the way!
    My Sako has a good sized magazine so that will not be a problem. I will also go with the standard throat length so that it will feed well.

    What barrel length and profile do you have on your rifle?
     
  12. woods

    woods Well-Known Member

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    I got a 26" #5 contour Brux barrel. The gunsmith cut in a brake/barrel port into the muzzle

    [​IMG]

    which is not as loud as a regular muzzle brake but does not reduce the recoil as much either. I installed a couple of mechanical recoil suppressors in the stock

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    which helped with recoil and balanced out the weight of the barrel.

    So it kicks about like a 300 win mag and is still carryable at about 10 1/2 pounds all loaded up

    [​IMG]
     
  13. Topshot

    Topshot Well-Known Member

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    WOODS,

    Interesting muzzle brake idea.

    With that muzzle brake/port machined into the end of the barrel. How much effective barrel length do you think was left up to the muzzle crown, after the machining work?

    The brake/port looks like about 1 1/2 inches long???
     
  14. woods

    woods Well-Known Member

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    It is 1 1/4" from the muzzle to the recessed crown at the bottom of the port. The barrel itself is 26" with the port so it is really 24 3/4" from case head to crown.