I remember an old guy at a long since closed range, He would come in with a Sheutzen Rifle (However yo spell it) He would hand seat a bullet in the barrel from the breach, carefully work a B&M measure that he had clamped to his toolbox, then pour the powder into his case. He would fire the rifle, whack out the primer and seat a new one then start the whole process again. He was shooting from the bench with irons, his groups were better than 95% of the scoped rifle guys. It was amazing, sub MOA at 100rds, from an ornate rifle that looked to be 100yrs old.
I have never owned a B&M measure but always wanted one. I have an old Herter's micro adjustable, a Redding BR, a few Lees and a Little Dandy. All get the job done, if I am having trouble with large extruded powder I just throw light, trickle to finish as I weigh the charges. Most times loads are not that critical. I shoot a lot of ball powder these days....the stuff measures like a dream, only problem is leakage from around the Lees.