Question about 7RM reloading

bstomper

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Joined
Sep 20, 2011
Messages
253
Location
Saskatchewan Canada
I am doing load development for my Winchester model 70 7mm RM. I am using Hornady brass, H1000 Federal 215m primers and 175gn Accubond LR bullets. Initial COAL is 3.360". I shot yesterday in -4c temps. The Nosler data says 65.5gns is max for the 175's and Hogdon and barnes say 64.5gns max at a COAL of 3.290". I am at 70.0gns and have no signs of pressure yet. No sticky bolt, no cratering on the primers but I can begin to see just a slight flattening of the primers. I am sitting around 2920 for speeds. I have a great accuracy node that is worth exploring at 68.2-2894fps, 68.4-2899fps and 68.6-2889. It confuses me a bit that I am 5gns above the stated max charge and not seeing pressure. Is this common? I could understand maybe a couple grains because of the longer COAL but 5 seems like a lot. I'm not to sure if I should continue to go up in charge weight until I see definate pressure signs and back down from there or just continue with the node at the 2890fps. Any help would be appreciated.
 

Gwine

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Joined
Mar 3, 2013
Messages
421
Location
Southern Oregon
I agree, don’t look for max in the cold. Be careful when it warms up even with H1000.

That said, I have a factory barreled 7RM that pressures up late. I’m currently running 4+ grains of 7828ssc over Berger’s data for my combination of components. My speed is within 30fps of the Berger velocity at max. This was developed at 80*.
 

bstomper

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Joined
Sep 20, 2011
Messages
253
Location
Saskatchewan Canada
I have more rounds loaded already at higher charge weights that I am going to pull the bullets on. Problem is I’m running low on bullets to do the next round of testing and won’t be able to get any for a couple weeks. Will I get accurate results if I use the pulled bullets in the load development
 
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