New cartridge series- based on the .338 Lapua??

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by CanadianLefty, Mar 25, 2004.

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  1. CanadianLefty

    CanadianLefty Well-Known Member

    Mar 2, 2004
    All the wildcat discussions based on the Lapua case have got me's this for a custom hunting rifle series:

    1. .257-338 Lapua mag, improved 40*What velocity, bullets etc. might I expect to get\use? Anyone have one of these? For deer, antelope etc...

    2. 7mm-338 Lapua mag, improved 40*for mulies, sheep, etc...

    3. 30-338 Lapua mag, improved 40*for elk, moose etc...

    4. 375-338 Lapua mag, improved 35*What velocity, bullets etc. might I expect to get\use? Anyone have one of these?for grizzly, African game etc...
  2. Varmint Hunter

    Varmint Hunter Well-Known Member

    Dec 26, 2001
    I'm sure that the 257-338Lapua would be great for at least 2 or 3 antelopes before the throat burned out. [​IMG]

    Even the 7mm-338Lapua would have a rather short season, if you know what I mean.

  3. STL_Shooter

    STL_Shooter Well-Known Member

    Nov 1, 2002
    I know the 30 cal variant works, and works extremely well. [​IMG]

    The 375 might have some merit - advantage to brass life. Accuracy...well, the bullets will limit you there.

    The smaller two... Well the 7mm may have some promise - Len will show us soon. It may be too much capacity for the current powders we have.

    And the .257? I can't imagine a powder of the correct burn rate to fill that case up and give you the velocity you'd want at a pressure you can live with. It's most likely just too big a case...
  4. Guest

    Guest Guest

    Actually, 3 out of the 4 have almost direct comparisons available.
    7mm Katzmaiar (7mm Lapua) one I forgot about.
    7mm-338 Lapua = 7mm Rem. Ultra Mag
    30-338 Lapua = 300 Rem. Ultra Mag
    375-338 Lapua = 375 Rem. Ultra Mag
    257-338 Lapua ~ 257 STW+20 grains (blowtorch)


    [ 03-26-2004: Message edited by: Crispin Goodall ]

    [ 03-27-2004: Message edited by: Crispin Goodall ]
  5. CanadianLefty

    CanadianLefty Well-Known Member

    Mar 2, 2004
    Does the 7mm Katzmaiar = 7mm-338 Lapua?Or does it achieve the same velocities but based on a different cartridge?

    The 375-338 Lapuashould have longer case life and achieve better accuracy than the 375RUM due in part to better brass cases. Any thoughts on this?

    Re: the .257-338 Lapua:
    Anyone have data or charts for the .257 STW? How probable is it that the .257-338 Lapua will be too hot for current powders and rifles? What velocity might it achieve using 115gr. VLDs and is 30" barrel sufficiently long for it? Upon considering this, would a 6.5-338 Lapua shooting 140gr VLDs be a better cartridge??

    Thanks Crispin and all! [​IMG]

    [ 03-27-2004: Message edited by: CanadianLefty ]
  6. Guest

    Guest Guest

    In the order asked:

    - The 7mm Katzmaiar is the 338 Lapua necked down to 7mm.

    - I am encountering no problems with cases or case life with the 375 RUM. Remington's brass seems to be quite good insofar as quality is concerned. I weigh and sort them but find that they are very close in weight so I quit sorting them. Besides, with the volume of powder used, weighing cases for accuracy falls into the law of diminishing returns. The chamber is cut relatively close to the brass size to eliminate excessive re-sizing, yet the cartridges feed nicely from the magazine.

    - Loading the 257-338 Lapua would require something along the lines of H50BMG or Vit. 20N29 for this small of a bore.

    - Here is a list of resources for the 257 STW: (33 loads)

    I hope that this helps a little.