A customer asked me about lapping his 22 rifles. He wanted to know if he should clean them first, or if he could just start lapping. He also wanted to know if the copper-washed 22 ammo commonly sold would be ok to use for lapping.
Lapping is going to clean like no cleaner ever made. Just start lapping if you can't see visible lead in the bore. If there is visible leading in the barrel, remove it with a strands of copper or brass kitchen scrubber wrapped around a worn out cleaning brush. It will only take a few strokes. This is also the best way to remove lead from any gun with a leaded bore.
The copper wash on 22 RF ammo won't hurt lapping, but the best ammo for lapping doesn't have the copper wash.