Sometimes powder doesn't come out of the measure on one operation, but lots of powder comes out on the next operation. The series of events varies, Ex none-lots, or none- none-lots, or none-little-none-lots.
I've seen this with SR4759 for years, never recorded what happened until recently. I have reports on bridging with surplus 4831, Red Dot?, and 700X.
I would like additional experiences including exactly what happened with what powder and measure.
Thanks;
joe b.

I have had 4759 bridge. It dropped a light charge and on the subsequent charge it dropped a heavy charge (what was left in the drop tube from the light charge + the next "full" charge).

I mentioned to a couple of "old timers" at Etna Green and they both suggested that I take a rat tail needle file and shape the interior of the drop tube to an oval shape. It TOTALLY  solved the problem. This was with an older Redding micrometer measure with a clear plastic drop tube.

Dale53

There is certainly a connection between the diameter of the hole in the drop tube and bridging. Some of these measures, with small drop tubes, bridge most reliably. The Redding BR30 drop tube is pressed in and would not dispense SR4759 without bridging. After opening the hole with a 5/16" bit the bridging stopped.
But. SR4759 bridges infrequently in my Lyman 55s, infrequently means that I ran ~150 test charges through without bridging. 
So on one hand we have the almost-always case, and on the other we have the almost-never case. 
I have an example of bridging with surplus 4831 once in the middle of a long string of charge.
Perhaps this forum is the wrong place to ask the question, SS guys don't use a lot of big-kernel extruded powders, correct?
Dale, what measure were you using?
Thanks;
joe b.