Rather than chemical strip try a penetrant like Kroil and a stiff bronze brush. I've had hunks of lead break free this way.

Drop the barrel in an ultrasonice cleaner and cycle it until all the lead is out.

charcoal bluing is done in excess of 500 degrees and color case hardening is done at around 1300 degrees, you probably would not need it to get that hot to loosen the lead (maybe 400 degrees?). You will probably compromise the finish, but that can be easily fixed.

Have your buddy shoot some fmj through it.

I would worry about hydrolysis brittle-ing using that system.

Last year I bought one of those Italian 92s imports. It had horrendous lead fowling! I thought the barrel was finished. So I started shooting it anyway (copper jacketed rounds), and every time after a range trip and a cleaning it would look better and better. Sometimes long pieces would come out that would actually follow the curvature of the rifling. I had never seen anything like it!

Well, the barrel is still far from perfect, but getting better every cleaning. The gun is more accurate than I, fowling and all.....

thinking about this in my sleep.......how hot was the lead when it fused itself with the metal in the barrel? 150-180-200 degrees maybe? I'll bet that the same amount of heat would release its grip on the rifling

This really validates what I wrote above. Forget trying to dissolve the lead chemically or with heat. Try a stiff brush, three or four spray penetrants, just soak and repeat.

Despite fouling vs fowling...........

Fouling! I knew that :)

"Fowling" is when birds get stuck in your pipe or when doves are used instead of gerbils for filling your "prison safe"

Could you please enlighten me on this. I have been using this system for years without any problems. Some guns I have used the system on twenty or more times and I can find no damage to any guns that I could attribute to this system. When I first started casting bullets I tried many combinations of lead, tin and antimony and found out that lead has many possible hardness levels. Fouled my Ruger out badly on several occasions. I hate spending hours scrubbing on a barrel. A good friend of mine showed me this unit and it works without any wear on the barrel.

Nice!

Most electro chemical reactions target the softest or particular molecule FIRST that does not preclude it from working on everything else at least over time

That's exactly how you would remove lead buildup from polygonal rifling.
I first soak the bore overnight in Aerokroil then clean as normal. The Aerokroil will help to lift off much of the lead by migrating underneath it. Then simply shoot some copper jacketed ammo.