Lapua vs RUM Case Capacity

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by barnesuser28, May 26, 2012.

  1. barnesuser28

    barnesuser28 Well-Known Member

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    i filled a hornady 338 Lapua case, a Lapua 338 Lapua case, and a remington 300 rum case with water until i got to the neck/ shoulder junction. i then dumped the water out onto my powder pan and measured the weight on a redding balance beam.
    this is what i got:

    Hornady 338 Lapua, 105 grains of water.

    Lapua 338 Lapua, 104.4 grains of water.

    Remington 300 RUM, 102.2 grains of water.


    I know the case capacity of a 338 EDGE case is probably different but i dont see how a 338 EDGE could outperform a 338 Lapua with the same barrel length, same bullet, and the same powder.
    From what i understand the 338 Lapua case can handle higher pressures than the Remington. i know Shawn C's 338 EDGE + P will whip the Lapua's butt any day of the week but i cant see how the standard 338 EDGE could beat out the Lapua. I'm not trying to affend anyone i just cant wrap my head around this.
     
  2. Broz

    Broz Well-Known Member

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    I don't know who told you the EDGE was faster than the LM, as far as the ones I have worked with they are virtually the same for velocity and load info.

    Jeff
     
  3. barnesuser28

    barnesuser28 Well-Known Member

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    i read somewhere on here that a 338 RUM can keep up with the Lapua and that the EDGE will easily exceed the Lapua. i dont remember where i read it but i was doubtful myself, thats why i decided to measured the case capacity of the Lapua and some 300 rum brass we had.
     
  4. Good

    Good Well-Known Member

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    My memory's not that great, but I remember reading loading data and coming to the conclusion that the RUM is generally appx 50fps slower than the Lap and Edge, but the Lap and Edge are similar.
     
  5. Augustus

    Augustus Well-Known Member

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    Even more of a mystery is where the Pedge(new term) gets nearly 300 fps increase over the standard Edge. If it is just a long throat and modified land angles I can't see how that much can be gained. Also if the gains are real it seems to me any cartridge would see the same gains if modified in the same manner. This would bump the 338/408 with the 300 gr bullets up around 3600 fps.

    What length barrel is used on the Pedge that produces 3130 fps?
     
  6. barnesuser28

    barnesuser28 Well-Known Member

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    From what i heard Shawn is using some sort of new top secret powder to achive those velocities. If it is temp stable i may just try it in my dads 338 Lapua. My guess is it would increase velocity by 100-150 fps in some guns.
     
  7. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    The 338-300 RUM and 338 Lapua loaded to the same pressures are virtually identical performance wise. The Lapua is typically faster because people tend to load the Lapua brass a little hotter with the same or better case life. The lapua is the better cartridge for several reasons. The 338 RUM has slightly less powder capacity than either of the other two but not much and performance between the three are all so close individual barrels make more diffence than there is between the cartridges.

    If the plus P changes performance it would be the same change with all of them so again basically all about the same. They are all so close either will do anything the other two will. All are equally accurate and share many of the same accuracy loads.