There are some modern copper clears out, Bore Tech eliminator is one. Its a sublet approach that is no haz and non toxic.

I have cleaned up old military barrels to where they gleam with it (and Carbon Killer 2000 thought the Bore Tech has a carbon cleaner component as well so it gets used first.)

I have yet to see real evidence that other than bored soldiers using steel rods from the front of a rifle cleaning does any harm.

Me? I don't want a big build up of carbon, so I clean after each shooting session (50 shots per rifle or more) . If its under 30, no.

What is funny is you ask top shooters what they do and not one of them agrees on the right way.

We launch a copper slug down the barrel at 2500 to 3500 fps and we think a coated rod is going to wear out steel?