Ive got four ecm barrel guns and ive pirated a technique from someone on this forum (cant remember who gets the credit for making this up).
I shoot almost exclusively lead and even with a decent lube grove filled leading happens, always in the last inch or so of barrel.

The FIX: Cut a furniture pin or some dowel down to the barrel size and then cover the dowel with a latex glove finger or similar piece of latex. Place the newly made plug into the forcing cone very firmly and place a small rag under the plug to catch spills, ( barrel should be completely verticle). next fill the barrel with a solution of half white vinegar and hydrogen proxide, ( check for leaks and possibly adjust your plug). Refill barrel as necessary and wait a half hour, then dump out all your lead. After this make sure to lube your barrel before storing or shooting and make sure your catch rag didnt let any spill into your frame.

THis is perfectly safe for all revolvers and cleans it better than anything else.