PFFFTTT, this thread just made me remember I've shot down a couple of drones already.
Well, they weren't self propelled, but pulled by another plane on a tether.
We had to qualify with the quad .50 twice a year. I got lucky and got there the week after, and had to qualify again a day or two before leaving.
I've shot down a BAT (ballistic air target) with a Stinger missile, does that count?