The scope was developed by taking the best features of the German system and combining them with those of the American system. The Japanese came into the picture because their lenses tested to be superior to even the German lenses. As Dan pursued his study of scopes and developed his Dual Reticle system he discovered some amazing things that could be done that would soon obsolete the present scopes on the market and revolutonize the design of rifle scopes and their’ reticles.
The dual reticle range finding fire control optics work through all powers. In addition each reticle monitors the other and tells the shooter if anything inside the scope has moved. Once zeroed, the reticles will stay aligned with each other unless something inside the scope moves. That means that as long as those two reticles are in alignment the interior of the scope is on the money. You now know where to look if groups began to spread or shots are missed. Look at the base, ammo, barrell bedding, etc. Because if the scope reticles are still in alignment the scope is still zeroed. Shepherd is truly the most reliable scope in the world.