30 sherman magnum


Well-Known Member
Jan 22, 2021
Rock Springs Wyoming
I've settled on a load for this 30 Sherman Magnum. I'm running a Archimedes action, 28" 8 twist chambered by straight jacket Armory, timney calvin elite 2 stage, KRG X-ray, EC tuner brake, atlas cal, wiebad mini fortune cookie bag, Vortex PMR rings and a Bushnell XRS ii.
Tonight I was verifying velocities and the tuner brake setting. A few nights ago I dialed in my powder charge and settled on a seating depth. Thank you Rich @elkaholic for pointing me in the right direction on seating depth. See results below.
30 Sherman Magnum ADG brass
225gr ELDM's
215m lmrp
225gr ELDM's jumped 0.040"
77.8gr RL26
CBTO: 2.890"
COAL: 3.675"
25 shot data:
ES: 25
SD: 6.1
Avg: 3028fps
First set of shots were 0.1gr jumps from 77.6gr to 77.9gr of RL26. I had 2 strings per powder charge where 1 had 0.025" jump and the other had 0.035". I picked the middle of the pack powder charge to build off of with a little more jump.

Shots from tonight to dial in the tuner. I am going to run it on setting #4 for now.

Not my best night for groups, but good data either way. Been battling a nasty cold for the past few days...that's my excuse lol.

I might have to use my IMR7977 at the rate I've been going through consumables. I'm down to less than 5lbs of RL26. The IMR7977 was doing well and was within 15fps compared to the same powder charge of H1000 on my 300PRC barrel. I might even have to swap back to my other barrel (300PRC) if I don't get decent results with 7977 and this 30SM barrel. Who knows with the powder situation. .

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