Anyone one use either IMR4831 or IMR4350?

Bobby B.

IMR 4831 and IMR 7828! Large case... too much air space

Reloder 19?

With that much case volume you can use a pretty slow powder. I would start at least as slow as H-4831. IMR-7828 SC is a pretty handy powder to use, so you might give it a try.

My now retired gunsmith buddy must have built a dozen or more of those 6mm/.284s. Bolt Actions. Mine is on a Mauser 98. He liked it a LOT. He would get one shooting and rave on it and out would come someone's money and he was off to build another.

His choice of powder was ONE. IMR 4350. He would dip the case full and seat a bullet. These were varmint bullets. I doubt he did this with 100 grainers, but that never came up. I loaned him a Chrony and he was surprised to be getting 3900 with 70 grainers; Hornady I think. Said the load was not "hot" but he thought he'd back off a trifle anyway. Barrel life.

And during one build, he was shooting a lot. Must have been. Gave me over a dozen empty powder cans. All the brown IMR 4350. (I am a pack rat...) SO it might work as well for you. Each gun has its own personality, but his all leaned this way. Luck.