You can check handloads for concentricity by rolling them on a concentricity gauge, checking the bodies, necks, and bullets for their degree of runout. Sizing dies, presses, shell holders, and bullet-seating dies are potential sources of crooked handloads. To reach your accuracy goals, you might have to sort your handloads based on their concentricity. Even the most carefully crafted handloads can vary in concentricity by .006 inch. Select those that have no more than .003 inch of runout to start.