mrat,
This may be far fetched, but when I first started shooting a revolver, I was shooting from a bench rest, and resting my revolver too close to one of the 4X4 shelter uprights. Got a face full of paint particles and splinters on the first shot, and thought it was the gun at first! Fortunately, I always wear safety glasses when shooting!
The gas escaping from the cylinder gap is traveling at thousands of feet per second, and can easily cut through wood, paint, sandbags, and even plastic bench rests!
The high speed pictures I've seen of revolvers being fired, show almost all of this escaping gas traveling at right angles to the cylinder/barrel, so spitting should not hit you in the face, unless it's being deflected by something?
Bill