WB
In that ctg. teh slowest pistol powders are a start
Tuesday, March 20, 2018, 07:09

then it progresses to medium speed rifle powders like H332 and AA2350 etc. IMR 3031 and such may be too bulky but I bet they would be toward the slowest you could fit under a bullet. With such a light projectile I'd start with the med rate rifle powders at somewhere around 80% volume under the seated bullet. The 375 Win. data could be useful as you would be ensured that the .400 GNR pressures would be lower. I used AA1680 (a slow pistol bulky powder) to very good effect with a 215 gr. bullet in the .375 Win. My first try was well over 2000 fps for a cast FNGC.

Sean did the initial ground work and it is sound data I'm sure.


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