loaded round has given some good info.
I have several guns now that use moons or half moons. I totally prefer the full moons.
And as for the demooning tool,, MAKE ONE! It's easy. A golf club handle,,, cut to about 8"-10" long,, and cut a notch of about 1/3 to 1/2 of the way around the edge,, about 1/16" deep, and it'll be a charm.
And as for mooning tools,, There are several out there,, and if you are planning on doing any amount of shooting,, buy one. I have 3 of them myself. Saves fingers & such.