Well Joe, you're way better than I am at cleaning lead already! I rarely take my bore cleaning to the point of a patch coming out as clean as it went in! My hat is off to you!

joeb, FWIW the old strategy of using mercury preparations to "mine" the lead out of a heavily leaded bore may be of use.  There used to be a medicinal preparation of mercury in tallow or some similar greasy carrier that was used on skin disorders    It has long been discontinued as too dangerous for human contact, but there were formulae for making a gunsmith's version of the same "blue ointment" as it was called, to use in those cases where the "complexion" of our bores got grey. 

Disclaimer:  I have not used this method myself, only read about it and had Charlie Dell confirm in personal discussion that he had used it to good effect...YMMV!  8)

Froggie

For LOTS of lead, a bit of steel wool on a bronze brush will wipe it pretty much out.   To finish,or for a LITTLE lead, some fine abrasive, such as JB paste or one of the "lead-out" patches will do it.  I have used a little "flour of pumice" on a solvent-dampened patch.
I have  used mercury, but don't much like it partly on account of toxicity and partly because it is not easy to do.  You have to have all the oil out, so use some carburetor cleaner.   Then plug the bore and fill with mercury.  The mercury is re-usable, but it is really hard not to spill a little of it, so you have to be really careful.  Last thing you want is some tiny drops of mercury on your shop floor.  Can't safely vacuum it up, and if you leave it, it gets smashed into even finer drops -- oxidizes and becomes hazardous dust.

CHRIS
RGChristensen

Joe, wrap some #1 steel wool around a cloth patch. Make sure it fits the bore real tight. Run it back and forth several time so it conforms to the rifling. Pull it out and dip it in battery acid. Push it back in the bore and scrub the bore real good. Set the barrel in a corner and leave it for at least twenty four hours.  This should work for you.

Good luck!

         Joe. 

The  trick we use around here is to take one of those small "flakes" and rub it hard between thumb and fore finger. If it disappears it's carbon and if it doesn't it's Lead.

Pete

Plain-based lead bullet barrels, like .22 rimfire barrels, need to be seasoned. Even the best barrels don’t shoot to their full potential until they have been shot for a while. A major part of that is ironing your lube into the pores of your barrel “conditioning it” to your lube and alloy. You can over clean a plain-based barrel in the same way that you can over clean a rimfire barrel. The results are pretty much the same you now have to run 50 to 100 rounds through the barrel before the accuracy comes back to full potential. The same applies when you change lubes it will take 50 or so shots before the rifle “settles down” and shoots right.
  I clean my rifle until the carbon is gone and stop. When I am either breaking in a new barrel or putting one up for a period of time, after cleaning I run a patch of lanolin oil through the barrel to thoroughly coat bore.

40 Rod