I use ball powders in my Uniflow all the time. No leakage issues at all.
Yep, that's where the uniflow shines. I guess if the op was wanting to drop consistent charges of stick powder, I've been told the cheap azzed plastic lee is where its at. When one goes bad, you just toss it and buy another.
The Cheap Ass Plastic Lee Dippers is exactly what I have been using since the 90s.... and I have been happy with them since the 90s...
If it ain't broke, I have NO need to FIX it....
and I also get by with a 505 Beam Scale.... bought the entire set up from the Fred Flintstone Estate....