The first thing new high power shooters need to learn is their position which includes the anchor point to the rifle. Cheek weld or anchor point guarantees the eye is the same distance from the Rear sight every time you start to make a shot. The AR 15 has helped many new high power shooters to get started in high power shooting but the AR 15 is one of the hardest rifles to find a consistent anchor point . For most experienced AR 15 shooters touching the hair on the tip of the nose to the charging handle guarantees the shooting eye is in the same position and distance from the rear sight every time.