Good suggestion on burning some 'lube' and seeing what's left, MMonk. Hadn't thought of that, but of course, the lube is on the bore as the powder flame runs over it- flash-burns and must leave "something" behind. Perhaps some of these mixes is what causes people to have to wipe their bores to ease loading?
I was out at the range with Taylor yesterday, shooting our .45 target perc. pistols. Just for the heck of it, I tried some 200gr. REAL bullets, lubed with Lyman's BP Gold lube. I fired off about 20 of them in a row without pausing to wipe the bore, using from 20gr. 3f to 40gr. 3F, then went back to shooting a .440" ball and .022" denim saliva patch without missing a beat. I noted to Taylor how easily it loaded (when I expected it to be a bit crunchy - not at all), even though only the top band of the bullet I had been using, actually engraved the lands. They must have obturated enough that the lube- perhaps 3 or 4 years old, worked, somewhat at least - however there was no buildup of fouling from shooting the bullets, to injure the easy loading the patched ball.
Perhaps Mad Monk is on to something with residues left in some of these difficult loading bores.