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  1. #1
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    Jan 2012
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    Ruimsig, Johannesburg, South Africa
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    Default 77gr loads for AR - Results

    Hi All,

    I recently took delivery of the AR I always wanted. I started reading up on the 1:7" twist barrel and the heavier loads said to be stable at this twist rate.

    There is a trove of information on the GS forum that guided me and helped me with regards to using S321 Somchem powder and the dangers of following the given load data. Thank you all for that.

    My findings:
    Gun: Colt LE6940
    Barrel: 16"
    Twist: 1:7
    Optic: Trijicon MRO
    Cases: .223 PMP
    Bullets: Nosler 77gr HPBT
    Velocity: No readings taken



    Four shot groupings @ 50m
    Measured the smallest three shot groupings. Giving me grace on a single shot per group for using a red-dot and shooter error.

    23gr S321 = 12mm/0,47"
    Recoil was notably more than any of the other loads. Slightly higher than point of aim. Think I may be pushing it a little here with regards to safe load levels for an AR.


    22gr S321 = 9mm/0,35"
    Impressively, 4 x shots went into 11mm. Point of aim. Recoil was not notably any different to what I am use to.


    21gr S321 = 11mm/0,43"
    Lighter recoiling. Half inch lower than point of aim.


    Due to the results at 50m, I took the best of the three loads and shot a four shot group with the 22gr S321 load at 100m. A little difficult with a 2MOA red-dot but achieved a 33mm/1,29" grouping. Very happy with the results.


    Hope this will help guide someone else out there wanting to load a heavier load than the standard 55gr loads. These loads are based on my own investigations, use this data at your own discretion.

    Law

  2. #2
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    Default Re: 77gr loads for AR - Results

    Out of my previous ZM4 22.2 grS 321 gave an average of 2480 FPS

  3. #3
    User
    Join Date
    Jan 2012
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    Ruimsig, Johannesburg, South Africa
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    Default

    Quote Originally Posted by BigT View Post
    Out of my previous ZM4 22.2 grS 321 gave an average of 2480 FPS
    Many thanks T. 2500fps average should be a great velocity for this bullet weight.

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