I'd really suggest a shoulder and bullet comperator set. They have 420, 400, 375 and 350 shoulder gauges that cover basically every cartridge, and the set usually comes with 338, 30, 7mm, 6.5mm, 6mm and 22 cal inserts for checking base to give. Perhaps you already have these. Then you'd just need the shoulder gauges. These two components are a must for any aspiring precision hand loader.