In 100 yard firing test at the Leupold plant in Oregon Weaver repeatedly removed and reattached a scope using the Leupold QR mount. And each time they fired the scope returned to within a half an inch of the original point of impact on the target. Super close machining tolerances are at the heart of this patented lever mechanism. By turning the lever forward and eccentric on the lever shaft engages the bases of the ring. This pulls the ring down and forward on the base locking it solidly into its zero position.
The characteristic that distinguishes the Quick Release mount system from the Dual Dovetail and STD systems is the ability to remove the scope from the rifle and reattach it without the loss of zero (within 1/2 MOA). Machined steel construction - Supremely-close machining tolerances.