Unless you are loading sub gauge DON'T BOTHER.
12 and 20 gauge are not less expensive to load unless you can get components at real wholesale. You need to buy quantities like
8 lbs. powder
5 K primers
lead a ton at a time.
There really are no savings in 12 or 20 gauge clay busting loads unless you buy at wholesale, and that means large quantity's.
Unlike metallic loading shot shells are strictly a follow the recipe deal. No working up loads. It does not have as much "fun factor"
Before you jump in google shotshell reloading calculator. Plug in the prices you find for components. Now go to Wal-Mart and find clay target loads at 5.25 a box. Your choice.
Freedom is not free