If you are NOT measuring every powder charge...
Progressive presses will usually provide a space for a powder check die in your processing.
I specifically purchased a Dillon 650 because it has an extra die hole for the powder check die.
Even the simple Dillon powder check die will find something as small as a cleaning pin difference in powder volume.
A second approach is to weigh your loaded rounds, they *Should* be fairly close *IF* you aren't mixing brass, primers or powder, and you are using bullets from a manufacturer that's all over the place.
*IF* you are using mixed brass, bullets with little quality control, etc., AND/OR, you want a very specific powder charge then the ONLY way to double check powder is to weigh every single charge.
Hyper accurate factory ammo goes through at least TWO powder measurement devices before it hits the case, usually two for weight, one for volume BEFORE it gets near the case.
Since most of us don't want to buy a computer for a CNC controlled powder measuring process, we use droppers, trickler & scales which are slow but very accurate.
It's TIME vs. investment in equipment and education on how to keep that equipment running correctly, you choose...
