7mm RUM and H50BMG Velocity Data

dwm

Well-Known Member
Joined
Feb 26, 2003
Messages
756
Location
Texas
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 ]
 
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