Ditto on Lewis Lead Remover. It is far easier to use, the brass screen will not harm metal and you don't need a power drill.

I clean the chamber first with solvent to get the loose powder and lead out. Then run the rubber stopper with a brass screen in good condition, give it a twists with your hand and, presto, you're done.

It helps not to let the lead build up. However I am guilty of neglecting cleaning my revolvers. Generally they get cleaned once a year whether they need it or not.