Just a little FYI, during the Zulu war, the British used gatling guns. One of the battles took place where there was no wind to carry off the cloud of smoke from the BP. In order for the guns to keep firing, soldiers were placed near the muzzle with boards to fan the smoke away.
Where I've done most of my CAS shooting, they spray the targets white. In those clouds of smoke, the targets tend to disappear. One of the tricks I've learned is to look for the outline of a target. One time I was at a match where you had to shoot a hole in a piece of cardboard with your shotgun, then shoot at a target on the other side of the "wall" with your rifle. Yep, you guessed it, the cardboard caught fire. Made for an interesting run, They were able to put the fire out before the "wall" went up as well, but I did hear that the following BP shooters had to wait while some buckets of water where scrounged up just in case.