Thats kinda right, but why not do it right. And definitely dont go by rcbs instructions, turn die down till it has a cam over. Which is completely wrong.
You need to measure your fired brass with a Hornady headspace comparator and set your die up to only bump the shoulder back 2 thou from fired, for bolt rifles. With all rifle brass, including belted mags. Your brass will last longer and your ammo will be more accurate. Factory ammo is bumped back 8 to 15 thou usually so it fits in all rifles. No reason to do that in rounds made for a specific rifle. Semi-auto's bump the shoulder 3 to 5 thou.
Over sizing cases is the main reason people have case head separation and then they want to blame the belt. Once you set the headspace on a belted mag treat it as any other cartridge and set the die up to only bump the shoulder 2 thou.
I get 13 to 15 reloads in my 7mag with a warm loads. And then retire the brass before any issues. But I anneal it every firing also. The Hornady headspace and bullet comparators are neccessary tools for reloading imo.