Many of us didn't know about the carbon build up behind the rings on used high mileage motors and the need to remove that carbon before replacing the rings.
You do need to be very careful on setting the depth so you don't scrape or remove any aluminum from the pistons tsk
I use to soak the pistons in hot soapy water for a while to help soften the carbon and then use a broken ring to scrape it out after damaging several pistons due to not setting the depth correctly realcrazy
Murphy lurks and loves messing with us hot rodders whiney grin

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)