7mm RUM and H50BMG Velocity Data

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by dwm, Aug 24, 2003.

  1. dwm

    dwm Well-Known Member

    Messages:
    738
    Joined:
    Feb 26, 2003
    Hey guys, I have some 7MM RUM - H50BMG data.

    REM 700 action
    Choate Varmint Stock (screwed a 1 1/2"W x 8"L strip of aluminum under the forend and under the back of the Choate stock to help it ride the rest better, slides really smooth now.)

    Pacnor Super Match, 1 in 11 twist - 28 inch barrel, not counting muzzle break, fully bedded.
    Factory trigger set to 1.5 pounds

    Weather:
    Temp: 81-86 degrees, 60-70% humidity, close to sea level.
    Wind: 0-2

    Cases, full length sized with Hornady FL sizing die. Case necks turned to 0.012- thickness. Don't have a small enough bushing for the Redding neck die yet.

    Bullets seated partially into the lands.

    Fed GM215M primers
    H50BMG powder, all charges weighed to +0.1 grains
    Sierra 168 HPBT Match bullets

    Hodgdon H50BMG load data:
    Start: 94 grains Max: 100 grains

    Group 1 - 94 grains
    3134, 3303(?), 3104, 3238, 3210

    Group 2 - 94.5 grains
    3256,3143, 3224,3249, 3198

    Group 3 - 95 grains
    3228, 3236, 3244, 3226, 3230

    Group 4 - 96 grains
    3266, 3277, 3281, 3287

    Group 5 - 97 grains
    3260, 3251, 3258,

    Group 6 - 98 grains (new data from here down)
    3223, 3269, 3264, 3257, 3244, 3257, 3264

    Group 7 - 99 grains
    3310, 3294, 3282, 3273, 3280, 3281, 3291, 3309
    3292, 3300

    Group 8 - 100 grains
    3315, 3346,3336, 3336, 3309

    No pressure signs at all, no marks on any cases, good looking primers. Looks like I could continue safely above 100 grains. The temperature was a little low for Texas though, not sure how these will do in the mid 90s.

    Groups are getting smaller, several groups went ~1/2 inch. (Maybe my shooting is improving.)

    I guess the whole point here is that H50BMG is shooting as good or better for me than Retumbo so far. The H50BMG velocity is good and it has a definite pressure advantage.

    Will this help the throat/barrel last longer?

    Doug

    [ 09-03-2003: Message edited by: dwm ]