With powders like H335, Hodgon longshot, win 244, win 231, cfe pistol/223, I get a weight difference of less than 0.1 gr. Doesn't matter if the hopper is full, nearly empty, if it's the 1st round of the day or the last.
First, I take the droptube/flairing funnel and polish the inside to a mirror shine. Pay attention mostly to the upper funnel ensuring there are no swirls, tool Mark's, edges etc.
Then I take all the edges off the powder bar and polish the inside of it too. Then I spray static guard inside the funnel and the hopper. I also ground the powder die to the steel bench. On the 650 I static guard the powder check brass portion of the rod and polish it also and ground it with a jumper to the powder drop die.
I load full throttle 10mm loads on the 650, as well as full throttle 44mag and 45-70 govt on the 550. I also load match grade .223 on the 550 as hand weighed charges for the powder I use are barely noticeably more consistent.....on the chronograph I noticed no difference.
Large stick powders like H1000 are all hand weighed.....as is H4831 for my 6mm AI and are loaded on a ponsness warren metallic ii. But benchmark is fine enough it seems to meter close to within 1/10th so I use it for the .223.
I have loaded 7.62x51 on my 550 using 4064 and found no appreciable difference between hand wieghed groups and velocity within 300 yards. But I wouldn't totally hang my hat on those tests yet as they were measured in an auto loading rifle.
Anyway, if sitting and weighing is something you enjoy, that's fine.....but the drop system on dillon's systems can be as accurate as most people's scales.
Think about this, do you believe that the factory hand weighs each charge? Nope, they are dropped. And with the right powder and a little polish, you can too.