The Wheeler Engineering Professional Reticle Leveling System is a precision tool designed to allow a scope to be perfectly leveled on any firearm with ease. CNC machining, factory adjusted calibration set screws, anodized aluminum construction and protective molded case put this instrument in a class of its own. The system is comprised of two machined aluminum level housings calibrated to their integrated levels. The Barrel Clamp Level is attached to the guns barrel while the smaller Reference Level is placed on scope base, bottom half of a ring or other flat surface perpendicular to the vertical axis of the gun. The gun is then rotated until the Reference Level is aligned. The tuning adjustment knob on the Barrel Clamp Level is then turned until its level is centered to match the Reference Level. At this point the Barrel Clamp Level is calibrated to the guns axis.