I've been sitting on my 458 for a while now and I really need to develop some loads. I have looked on the 458 forums but I couldn't find much conclusive, especially for the Berrys bullets I picked up to start with.

I've got brand new Starline brass (well, puurrrdyyy nickel) and Berrys 350gr bullets. I have some RL7 that I was going to start with.

From what I have gathered on the 458 board, somewhere around 40.5gr of RL7 is max under a 350gr bullet. It seems like too low of a charge results in unburnt powder, so I was thinking about starting around 37.5-38gr under a 350gr Berry's bullet. The "chart" I have indicates that there is unburnt powder at anything less than 39.5gr. That doesn't leave much of a margin for error, hence my desire to start a little lower.

That sound reasonable? Anyone played with RL7 in 458? Or recommend another powder? I have a desire to go heavier and subsonic, but I had a hard time finding bullets back when I picked all of this up. I figured I'd start with the 350s and go from there.

IMR 4198 and 4227. 4198 max is spicy.

I use Lil gun with the berry bullets in my 458 socom.

28 grains.


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