AA's hulls, wiped with a little bit of silicon based furniture polish before match. STS's work, if your reloading don't buy any you'll find all you need in the trash at any good gun range. Brass are for cool factor only, not really pc and do take a bit more to load. They are also finicky if different shotguns are used. WARNING! Then there is the primer issue, i have personally had two or three spark off while setting them. Never had a 209 set off while loading them traditionally.
My favorite to load is a paper hull with a rolled crimp.
Dick's sporting goods used to give a discount in the case (250 rounds) of AA's .