Re: Powder measure opinions...
I agree that it doesn't get any better than the ball bearing Harrel. But, I believe the Harrel is made to move about 40 grains of most powders at a time, certainly not nearly twice that amount. So, I don't think it will be as good as you might hope for your large magnum.
Next, understand that ball powders measure easily but NO volume measurment of coarse powders can be consistanty done by ANY volume dispenser with high consistancy, it just ain't physically possible. In fact, for metering coarse powders, Lee's little "Perfect" powder measure may well be the most consistant tool on the market.
I believe a Redding measure, or Homady's copy of it, or the RCBS measure with a micrometer chamber will do as good across the board as most of us need.