OCW Load development, .338LM

Discussion in 'Reloading' started by ST42, May 16, 2008.

  1. ST42

    ST42 Well-Known Member

    Nov 11, 2007

    I thought that I would share some results from my .338LM that I have been working up loads for this past few weeks. I decided to give Dan Newberry's system of load development a try after seeing great results here from other posters. For those that have not seen Dan's web site, here is a link.
    Dan Newberry's Optimal Charge Weight Load Development

    I decided to use RE-25 for my trials and I'm very happy with the results so far. After running a few loads through Quick Load, I decided to start my OCW test using RE-25 @ 82.9 grns. I then made 3 grain adjustments up to 84.3 grains. After shooting my test rounds, it became apparent that my rifle was liking the charges at 83.5 and 83.8 grains. Both were very close to POA. Yesterday, I ran another test with 5 rounds loaded in 1 grain increments from 83.5 to 83.8 grains. Again, the 83.5 grain load showed the most promise. Measured @ 0.205 moa.
    These initial rounds were all loaded using New Lapua brass that measure out to 2.7115" with a coal from ogive at 2.880".

    Today I thought that I would see how the accuracy might hold up with changes in COAL. I determined my COAL to the lands with my lot of SMK's as 2.903. My first ten rounds were loaded to 2.983". The second ten were loaded to 2.988", .010" and .005" from the lands.

    I was pleasantly surprised by two aspects of my results today. First, I was able to drop my Average distance to center to .185 moa for a six shot group and .196 for a four shot group. I intended to shoot two 5 round groups but I got a little carried away with how everything was progressing. Second. I was able to pick up a very nice increase in velocity. I went from an average of 2631.60 fps to 2695.57 fps. and from an ES of 53.72 and a SD of 17.32. To an ES of 20.43 and a SD of 6.40.




    Both days shooting was at 62 to 65 degrees. Next testing will start to include longer ranges and hopefully more temp changes.
    But so far so good.

  2. sjadventures

    sjadventures Well-Known Member

    Dec 9, 2007
    I read the article at the link and that is interesting.


    ROB WHALLEY Member

    Oct 13, 2008
    Very interesting.I will be looking forward to see what your next results will be as i am about to start reloading for my 338 LM.
  4. green 788

    green 788 Well-Known Member

    Feb 5, 2005
    I'm glad that worked out well for you...

    What charge and OAL did you end up settling on?

  5. Dr. Vette

    Dr. Vette Well-Known Member

    Dec 30, 2009
    It's a 4 year old thread, and the OP hasn't been back to the site since late April. So, it may be a while before any more answers show up.

    I wish he had shown more of his groups from day 1 so that I could see the progression as he increased the charge. Also, the added-in markings cover many of the handwritten charge numbers.

    I'm hoping to try this with Dad's 7mm Wby so every time I can read someone else's report about the process I do so.