I don't think compaction is any problem with the .458. The loads I listed are not compacted very much, including the one with the 500 grain bullet above 2200 fps.

I am familiar with the old stories about WW748 powder clumping together after laying around the tropics for years, but that's far different from AA2230 fired maybe two months after loading. I don't use WW748.

I used to use a really compacted H4831 load for 1000 yards at Camp Perry, Ohio, using a 30-06 with 190 grain MatchKings. It gets a lot hotter and more humid at Camp Perry in August than it does during the usual hunting months in southern Africa. I never had velocity changes due to any compaction, which I am certain would have showed up at 1000 yards.

Don't blame me. I voted for Trump.

Democrats would burn this country to the ground, if they could rule over the ashes.