Leading in barrel requires no chemicals
To get lead out of a pistol barrel, you only need copper mesh wrapped around an old brush. If it's a tight fit, that will push the lead out of your barrel. Lead requires no chemicals to remove.
Once my barrel has been cleared of lead, I like to take a patch soaked with gun oil (I like Wilson's) and run it through the barrel. Then, take a clean copper brush (no mesh, just the brush) and run it through 10-15 times. Then run dry patches through until they come out clean. This will not only clean the barrel of all powder fouling, it will help prevent leading the in barrel the next time you shoot.
Brake cleaner is great for two purposes: 1) If you shoot copper jacketed bullets, brake cleaner will remove any remaining copper cleaner from your barrel (some guys prefer rubbing alcohol for this); and 2) With pistols, it's nice to spray the slide after you've scraped away as much powder fouling as you can. The brake cleaner will get into small cracks and blow out the remaining residue of fouling. Be careful not to spray plastic parts of a gun. Brake cleaner can "melt" plastic. I think someone makes a 'plastic friendly' version, but it's much more expensive than standard brake cleaner.
So no, brake cleaner doesn't remove lead.