Considering the sniper semi-auto vs bolt thread; No matter how accurate the tool it's the operator that determines precision. Now with that opinion out of the way I'm curious about ammo selection. I'm vaguely familiar with twist rates vs bullet weights and barrel lengths on accuracy. I know military sniper teams have their armory hand roll ammo tailored to a specific rifle. Now, us as lesser gods not having that luxury, how do you select your ammo for the highest accuracy? What gives an average to good shooter the best chance at repeatable accuracy? How do you select the top shelf ammo? There has got to be a more scientific approach then "see what your gun likes" which is probably acceptable for a pistol caliber carbine. Given a certain twist and barrel length how do I select ammo? In your experience what is the most accurate ammo in: 5.56/.223 .308 7.62x39 7.62x54r 30.06? As those seem to be the most prevalent on this forum.