.338LM Load Info Requested

Discussion in 'Reloading' started by VTi, Dec 24, 2007.

  1. VTi

    VTi Well-Known Member

    Jan 18, 2004
    Hello everyone. I have a .338LM GAP (30.5" tube) being delivered today and would like some help regarding load data, specifically powder selection.

    I know there's many threads out there with 338lm load info, but I think they're mostly shooting 27"-28" barrels. I'd like to know from some of you with experience loading for this, or similar, cartridges -- what's the best powder behind a 300smk to get the most efficiency out of this 30.5" bbl?

    I think I've narrowed it down to either RL25 or Retumbo. Any info would be GREATLY appreciated.

    Thank you, and happy holidays to you and yours.
  2. wc872

    wc872 Well-Known Member

    Apr 26, 2006
    338 Lapua

    Congrats on your new rifle. I've only heard really good things about GAP. As far as reloading goes. Start low and work up. 300gr. SMK work well with RL25. I've used Rem 9 1/2 Magnum primers for the last few years and am very happy with them. Ramshot Magnum, H50BMG, H1000, VV24N41, & N170 all work. Lapua 250gr. Lockbase should be tried I think. Also had good luck with 225gr. Nosler Accubond for hunting.
    Semper Fi

  3. G-gear

    G-gear Well-Known Member

    Jan 27, 2008
    light bulbGet the Sierra manual:
    Sierra Bullets - The Bulletsmiths

    338 Lapua Magnum
    Savage 116 rifle, 26" barrel 1x10" twist
    Trim to length brass 2.714"
    Federal 215 primers
    Max COL 3.680"

    Sierra lists three bullet weights: 215-gr., 250-gr., and 300-gr.
    Sierra Bullets - The Bulletsmiths
    215 SBT (Spitzer Boat Tail) max velocity 3,300 fps - ME 5,200 ft.lbs.
    250 SBT (Spitzer Boat Tail) max velocity 3,000 fps - ME 4,997 ft.lbs.
    250 HPBT (MatchKing) same as SBT
    300 HPBT (MatchKing) max velocity 2,750 fps - ME 5,038 ft.lbs.

    I assume that you will be using match bullets, so, here's Sierra's load data for Retumbo (No Reloader 25 data listed).

    [26" barrel]
    250 grain HPBT MatchKing
    Retumbo 89.6 = 2,750 fps - ME 4,199 ft.lbs.
    Retumbo 92.1 = 2,800 fps - ME 4,353 ft.lbs.
    Retumbo 94.6 = 2,850 fps - ME 4,510 ft.lbs. Max Load.

    That's all they have for Retumbo. And, only in that bullet weight (250 grains.)
    I would get the Sierra manual, and try other powders for more velocity and/or accuracy.
    After finding the best accuracy load, I'd chrongraph that load, and plug in that load data into Sierra's software "Infinity" to find the trajectory and other bullseye info for your custom load/weapon.
    Sierra Bullets - The Bulletsmiths

    Maybe this will help:
    Sierra reloading data 338 Lapua - Google Search

    Good shootin'!
    Last edited: Jan 27, 2008
  4. phildo6000

    phildo6000 Member

    Jun 13, 2005
    I am loading 88.5 gr of RL25 behind a 300SMK with 215m primers with lapua brass. My gun shoots 1.1 to 1.3 inch groups @ 300yds with this load. My gun is a CZ 550 416 action with a 28" Loather Walther barrel on it. Nightforce 5.5-22x56. no brake and can shoot all day long. Don't know the velocity, but is very accurate.
  5. dbrush

    dbrush Member

    Oct 31, 2007
    Sierra 300smk over 86grn RL 25 Fed 215M.
    Has been outstanding in several rifles
  6. BHP9

    BHP9 Well-Known Member

    Dec 4, 2007
    I'm having success Using H1000 and a 92.5gr weight under a 250gr Lapua LockBase or Scenar.