Re: Looking for one well suited pistol powder.
While Unique is often used for fractional rifle loads to achieve perhaps several lower performance goals, I've found that most 'dirty' powders tend to clean up quite a bit as loads get fair to near max. It could be that bullets which obturate and expand more fully under full pressures may tend to 'wipe' the bore more efficiently.
Again, it is important to allow the solvent to take its time about working its magic.
One other thing I've concluded is that aside from thoroughly spreading solvent into deep crevices, like the bottoms of grooves, brushes are kinda overrated. For my intents and purposes, nylon brushes are probably completely adequate for the matters where I consider brushes to have benefit.
I think the concept of 'scrubbing' glazed fouling out with a brush is not especially effective, and may be harmful if cleaning rod/bore/throat contact is occurring sumultaneously.
Bronze brushes my have some value if used after some solvent soaking as a means of dislodging softened fouling, then patching the bore and following up with more solvent soaking.
Greg