338 Norma Improved.

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Rhovee, Dec 7, 2019.


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  1. Rhovee

    Rhovee Well-Known Member

    Messages:
    806
    Joined:
    Jun 29, 2017
    Here is some info I have for 338 NMI.
    I am using:
    24” barrel
    Lapua brass
    CCI 250’s
    300 grain EH Berger’s
    Built by Alex Wheeler
    Fire formed with 300’s +.015 in the lands with
    85 grains H1000.
    I started with H1000 and have excellent accuracy at typical non improved speeds. Ran up to 2830 before bolt click. Shot best at 2720 with 1” at 300 yard groups. Had one 3/4” group.

    Then I tested some N570. Never did hit pressure, case gets to full. At 94.5 I can feel a slight crunch with powder while using 6” drop tube. Attached is a picture of a seating depth test I did tonight. There is some good consistency with accuracy and velocity in these groups. Total of .015 seating depth and all shot well. All shots had an Es of 20 and I might try Fed 215 and see if that changes. If not I will wait and shoot it at 1k and see what works the best.

    Powder numbers;
    H1000
    89.5-2700 (Accuracy)
    90-2715
    90.5-2744
    91-2750
    91.5-2785
    92-2810
    92.5-2810

    N570
    91-2690
    91.5-2704
    92-2730
    92.5-2759
    93-2775
    93.5 2772
    94-2800 (accuracy)
    94.5-2820 (accuracy)

    Figured someone would be needing this info
     

    Attached Files:

    Rick Richard and JJMoody like this.
  2. snox801

    snox801 Well-Known Member

    Messages:
    2,781
    Joined:
    Sep 19, 2012
    I like that round. Might be worth giving rl33 a try most my large capacities like that but the 24” tube may be a bit to short with that powder.
     
    Lahunter76 likes this.