You could get one of the electrolysis type cleaning devices but they are somewhat costly. JB's bore paste will help remove lead too - eventually. However, a muzzleloading barrel maker of note put me onto using regular kitchen type Scotchbrite pad wrapped around a cleaning rod or dowel of appropriate size. He says it won't harm the steel and I know he regularly cleans his chunk guns with it. (Chunkguns are sort of the ancestor of benchrest rifles). Preventing the leading is a function of proper lubrication. When you select cast bullets get those with wide lube grooves so they can hold enough lube to work properly. Many cast bullets have grooves too narrow to hold enough. The blackpowder cartridge rifle shooters learn quickly to select the correct bullets and make sure the lube is fresh and plentiful. Their velocities are greater than anything you are likely to generate in a handgun and the lube works for them to prevent leading of very soft lead bullets. If you have enough lube, one indication is a star shaped smear of the stuff on the outside of the cylinder and around the muzzle.
