338 ultra mag improved

Discussion in 'Gunsmithing' started by bama4570, May 4, 2007.

  1. bama4570

    bama4570 Member

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    Can I use a standard Savage action to chanber this round?
     
  2. James Jones

    James Jones Well-Known Member

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    Well this is kind of a loaded question , yes it can be done but I would reccommend fitting the barrel to the action like the Rem barrels do thus eliminating the barrel nut.
    Savage did make some RUM's mags and WSM's with the standard small shank but quickly changed to the larger shank that they are found in today.
    I have heard of cases that the small shank guns chambered in the RUM's had split the barrel nuts in some higher pressure rounds and supposidly this is why Savage went to the bigger shank and kept the barrel nut instraed to just fitting them up like everybody else.

    Now a question on your cartridge choice , why do you want a 338 RUM improved?
    The reason I ask is that the RUM case desgine is already very effecient and little gain will be had by improving the 338 RUM. You will have to fireform you brass to get all the benifit out of it and that eats up barrel life and is time consuming and all for very limited increase in power.
    You could go with the 338 Edge which is a 300 RUM case thats necked up to 338 , the 300 RUM case has more powder capacity than the 338 RUM case thus giving you a boost in velocity with the increased powder and their is no fireforming.
     

  3. bama4570

    bama4570 Member

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    James,

    Thank you very much for the info. The improved case gives a increase of 10 grains of powder. The choice calibers was to try to get 3000 fps out of a 300 gr match king. I have found some posts on the 338 edge improved and my go with that. I am still in the information gathering stages of my project.
     
  4. jwp475

    jwp475 Well-Known Member

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    [ QUOTE ]
    James,

    Thank you very much for the info. The improved case gives a increase of 10 grains of powder. The choice calibers was to try to get 3000 fps out of a 300 gr match king. I have found some posts on the 338 edge improved and my go with that. I am still in the information gathering stages of my project.

    [/ QUOTE ]

    How can you get 10 more grains of powder in a 338 ultra improved? Thats more than the 338 Edge's powder increase (6 to 8) and it is a longer case, and there is minimal improvement to be had as James Jones pointed out.......
     
  5. James Jones

    James Jones Well-Known Member

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    Yea I think that gaining 10 grs for Ackley improving the basic 338 RUM case might be a bit much. You could probably improve the 300 Rum case fater its necked up 338 and gain a wee bit more than the regular RUM case but if i were gonna go through all that trouble I'd build a 338 Lapua improved as you'll be able to push the pressures a bit higher without wrecking the brass as quickley.
    The next step for an increase in powder would be the 338-378Wby or the improved version of that , then the problem comes back to the weak brass that VERY expensive
     
  6. 1doug

    1doug Well-Known Member

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    whats so magical about the 300 mk going 3000fps? the edge in a 28 in barrel will get you to 2900. the extra 100 fps is trivial at best.

    d-a
     
  7. Wild_Bill

    Wild_Bill Well-Known Member

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    Hi you are a bit optimistic with the 10gr extra powder capacity. I have an improved case called the 338WBX i am waiting on my wildcat 275 and 300gr projectiles but have been playing with 250gr Lapua projectiles. I have loaded them up to 102gr Retumbo in the full length 300 ultra case improved with a 60 degree shoulder and that is MAX i have also used 100gr H1000 but that is MAX and 98 works very well.

    I was realy surprised as these loads are supposed to be safe in a standard 338 Ultra mag. It does not add up. You cant get that much Retumbo into the 338 ultra cases. I am only fireforming in a take out 338 ultra barrel while waiting on my 30" fluted lawton to arrive and then asemble the whole rifle. I am also shooting it off my Model7 stainless synthetic action and stock i just relieved the barrel channel a little and it fits well. I bore sighted it at 300 yards with an old 3-9 Leupold and fired 3 shots 2 were touching and the third was dead flat out at 9 o clock making the group around 2.5" not to bad for just playing around.

    The load i am using for fireforming is 95gr H1000

    all loads are with Fed 215 primers and the loaded length is 3.850"

    Cheers Bill
    Australia