Bill,
Although RL-7 delivered some outstanding performance, I can't really say that it is necessarily the best powder for the heavier bullets. AA 2015 deserves some serious consideration and load development in given guns, as does Varget... perhaps it doesn't deliver quite the velocities, the uniformity was surprising with the heavier weight bullets. Too, with Varget, none of the loads listed were any where near max pressures!
As for bullet selection in the heavier weights, two top choices are of course, as number one, the 44-330g LFNGCDCG and second choice is the 44-325g LCMNGC bullet for accuracy. They are both excellent performers in the .444.
Absolutely no extra steps were needed to load any of the bullets listed. Interestingly, the new batch of Remington .444 bulk brass that I ordered was much thinner than the the last batch of brass that I obtained nearly twenty years ago. Surprisingly, even the big 405g WLNGC bullet did not require any inside neck reaming as did the old brass that I worked with for several years.
Things that are toothy and angry are in big trouble with any of these loads over three hundred grains. Bill, I wouldn't feel any preference at all, just the bullet that shot the best for a given gun! Any one of them is an awfully powerful load!
Mike... not to worry about the bullets... they were all culls! :biggrin:
Blessings to all!
Marshall