I'm going to tell you how I do it. Some people may dissagree but I think most will concur. You want to set the belt headspace tight to .002 loose maximum. Now if you plan on reloading the critical part to extend the life of your brass is either neck size only or use a full length sizing die but only bump you shoulder back .001 0r .002 thousandths. That will require a case headspace gauge like what hornady sells(and a dial caliper). The gif's that Biged posted tells the story of what happens if you dont follow those rules. Belted cases have their issues but if you get your headpace correct and keep you shoulder close to the chamber shoulder you will get long life out of your brass