223, it sounds like you're considering options for an AR for NRA Highpower competition. If so, you may benefit from my book, "Black Magic: The Ultra-Accurate AR15." It covers accurate AR's from the ground up: receivers, parts, barrels, twists, gunsmiths, chambering reamers, sights, triggers, float tubes, scope mts, handloading for accuracy, how to properly accuracy test the AR, 1000 yd. ballistics, experiments to show the true accuracy contribution of specialized techniques like turning necks, weighing cases, weighed vs. metered powder charges, progressive vs. single stage loading, tight vs. as-issued upper/lower receivers, etc. It is intended to help you get the most out of your AR without wasting time, money and energy on stuff that DOESN'T WORK. It shows what to realistically expect from factory barrels/military bullets vs. target barrels/ammo. (300 pages.) I give AR15.com'ers a $3.00 discount on autographed copies. If you'd like one, email me direct for details. Hope helpful, John Feamster, columnist, Precision Shooting/The Accurate Rifle.