I am assuming the projectiles exited the barrel?
Was their any unburnt powder left?
If not then I suspect you might be right about no powder dropping.
Do you have any left of the batch you reloaded, it might be worth weighing them or even shaking them to see if you can feel the powder moving about.
Dipisc, no the primers functioned. At least well enough to drive the bullet into the barrel.
Sledge, no the primers functioned well enough to get the bullet just past the forcing cone. I didn't see any powder but since it's only about 5 grains I'm really not sure. Mostly this happened in my revolver so some of the powder could have been driven out the gap. I should have been more careful in checking.
I tried weighing the cases, but since we're talking about +/- 5 grains and I use mixed cases it isn't always clear. I did find one, but missed 3 others.
Nope, I've shot that batch completely up. Other calibers loaded around the same time period show no problems.
I probably got distracted by the small primer cases and somehow just blew it.
Had a double charge yesterday with .44 magnum. For the life of me I can't figure out how I double pumped it. Fortunately, it was filled near the top and I knew immediately to pull that round. Maybe I'm going senile.