At the end of a recent DPS1 class, we were doing the extreme-close-quarters drill. As I walked the line I noticed something different on one student’s target.
Click to embiggen
You’ll want to click on the picture to embiggen it and see the detail.
He said he was shooing Blazer (I guess Blazer Brass). And at that “contact distance”, the bullet was spinning (hooray rifling!), thus the air around was being spun, all the unburnt powder was coming out… and there you go.
Pretty nifty looking, eh?
Stuff From Hsoi 
bonus points if they set the target on fire
that would r00lez
My J frame does that with most ammo at less than 2 feet. My XD will do that with Monarch, Blazer, or any really dirty round.
Makes sense. Less than optimal powders, short barrels so not enough burn time.
It’s pretty stuff.
I had that happen on some reloads in .357 using Berry’s plated full wadcutters. My thoughts was that the rifling cut through the thin copper plate, and there was some vaporizing lead spinning off the bullet as it flew. IIRC, it was not too close that it was doing it, either. maybe 10 yards.