I load prepped cases in operation blocks:
Prime them all
Charge them all
Seat all the bullets
Spin them all
By switching between operations case to case you may not have down time, but it's a good bet you use more time.
If +/- .1 grain of a Lincoln Log powder like 3031 is what's to be held, then I can "thweigh" charges using my measure and electronic scale. If one is off I don't waste time adjusting it, I return it to the hopper and throw again. Between 2/3 to 3/4 of the charges meet spec as thrown (yes, I've tested it many times), so it's quick.
