I've yet to find any measure that is consistent within 1/10th grain with any powder.
I also have a Uniflow, and it gives an average 3/10th-grain spread on Unique, AA #7/#9, 2400, Trail Boss... you name it! I have a baffle in mine, and it does help, but only if I do other things. I get the best uniformity with Unique when I fill just above the baffle so that there is a consistent weight of it over top of the cylinder. I've tried knocking the charge handle and other stuff, but no technique is as effective as making the weight on top of the cylinder consistent.
Even so, I generally individually-weight charges, and keep my trickler handy to even 'em out.