338 Lapua Ackley Improved pressure signs

Discussion in 'Long Range Hunting & Shooting' started by jskmtd, Sep 15, 2019.

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  1. jskmtd

    jskmtd Well-Known Member

    Aug 27, 2009
    I recieved my new 338 Lapua ackley improved and after fire forming some brass started working up a load. Rifle components consist of a 28" proof barrel and defiance deviant hunter action.The fire formed case has a h2o capacity of 121.7 grains for reference. I started with Retumbo, Lapua brass, and Berger 300 grain otm. At 95 grains of Retumbo and a coal of 3.805", which is .020 off the lands, I'm seeing faint ejector marks velocity was 2812 fps. At 96 grains ejector marks still faint muzzle velocity 2852 fps. Velocities taken with magneto speed. I was hoping to see more velocity than this, is this wishful thinking? I went up to 93 grains fire forming and didn't see any signs of pressure.
    Let me know if I should be checking anything else. Any ideas appreciated.
    Last edited: Sep 15, 2019
  2. snox801

    snox801 Well-Known Member

    Sep 19, 2012
    A lot depends on the design. But ya you should see more than that. My brother and I have lapua improved rifles and he has his load work done. I don’t so I can’t speak on mine but you should see higher than that. Usually around 200 FPS faster than what can be had with the standard case. I know he achieved 3100 plus with 300gr lasers but he also has a 34” tube.