Maybe you have fairy dust, or maybe you have an extremely smooth bore with a great finish (not what I experienced with traditions). But I think it's more likely that because you're using water and no type of solvent (soap, moose milk, bore butter), your actually just leaving a bunch of stuff in the bore. What I've found is that each of those gets the bore cleaner than the others, and clean with just one is not clean with all 3.
I strongly suspect that if I ran my cleaning protocol on your barrel after you cleaned it, a whole bunch of gunk would come out. If you're single patching only and those never ever get stuck when when dry, then I would about guarantee that it's not as clean as you're currently thinking.