I hate to bring this up this late in the thread, but most if not all
leading can be avoided by matching the bullet diameter to the chamber
throat diameter. The medium to hard alloys are useful here.
Dead soft lead might be needed for expansion but otherwise is
useless.
I have several 1980's 44's that have oversized cylinder throats.
Using oversized matching bullets eliminated leading almost completely.
I just run a patch or 2 with solvent to get rid of the carbon. Then
a dry brass brush for awhile in the bore. Another patch of solvent
and then maybe a couple with JB compound. It's clean. I have
never had streaking up the barrel, just some precipitation at the
cone. Polishing the barrel with JB helps too over the long run.

I shoot a lot of lead target loads and some husky ones as well
and have never had to clean more than the first inch of the barrel.
I must have in the past as I have some old used Lewis
parts but don't actually remember when I used them last (I'm
getting old).

Oregon Trail offers one of the widest ranges of bullet diameters
I know of. No affiliation, they don't even know me, etc.

I use their .431 44 bullets that actually measure .432. They
are enough larger that my Redding profile crimp sticks on them.
I am in the process of getting one .002' larger at the base.
Their seat/crimp die does work with these.

Increased accuracy and no leading. Time to break out that micrometer.

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Nemo