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Hornady 5.56mm 55gr GMX

Discussion in 'Caliber Corner' started by DRT, Dec 30, 2011.

  1. DRT

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    May 6, 2001
    I just got my 2012 Hornady LE & Military catalog and they've included the 55gr GMX loading in their catalog. It looks the same as the superformance GMX loading.

    Here are the specifics:

    Product # = 81255 (5.56mm pressure)
    55gr GMX (no polymer tip that's typical with other GMX bullets. It resembles a non-boattail TSX but with a larger internal HP cavity)
    B.C. = .245
    S.D. = .157
    Advertised Velocity out of a 16" test barrel):
    Mz = 3130, 100yd = 2739, 200yd = 2380, 300yd = 2049

    Gel Test:

    16" 1:9 weapon
    Measured Velocity = 3193
    21" Penetration (pretty amazing for a fully-expanded 55gr .22 cal bullet)
    Max Cav = 4" (not nearly as dramatic as the 75gr TAP)
    Depth to Max Cav = 5"
    Entry = 1"
    Retained weight = 55gr

    The bullet looked like a perfect mushroom. I suspect that the guilding metal construction will retain its petals through intermediate barriers better than a pure copper design . The profile of the mushroom looks more similar to a conventional bullet versus the TSX that has substantial gap between the petals. I bet this would make a good hunting round as well.

    By the way, the gel shot with the 75gr 5.56mm TAp 8126N still looked the most impressive of any .223/5.56mm round. It obviously remains a top pick for unobstructed shots.
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