Interesting question and topic. For my part, I've used Goex 2f and 3f briefly, and then Pyrodex P almost exclusively due to ease of getting it. Untill I started reading about accuracy, and trying to get my rifle to shoot under 4" at 100 yards ( a feat I may never get to but not because the rifle cant do it; the shooter cant do it open sight any longer) I never ever swabbed between shots.
In my early days I would spend several hours out shooting, and fire upwards of 30 to 40 shots out of my rifle. Back then I used pre-lubed patches with Wonderlube or other similar concoction I could buy.
To be quite honest, I only swab now about every 5 shots just to help with bore consistency for more accurate shots, (and I should swab every shot for that purpose I'm just lazy). Now that I think about it I am certain I had trouble at least once,but it was very rare and after several shots. Though I honestly couldn't tell you if it was before or after my switch to Pyrodex. I do remember Pyrodex RS being quite dirty so it may have been during the one or two cans of that stuff..