Re: resetting the zero on a falcon menace
RW snyder is the go-to guy for falcon issues. That said, i'm not sure they outright sell the turrets to upgrade the old scopes. The "new" turrets are all mil/mil, so if your old falcon was MOA, then your are not going to be able to use them anyway.
On the old ones, hold the knob and loosen the center screw. If you don't hold it, you'll turn the knob and lose your zero. turn the screw out pretty far, pull the cap straight up to disengage the splines. Turn to the zero mark (or close to it, they don't always line up exactly) and press the cap back down. Tighten screw.
The new ones have grub screws and are much stiffer turrets so they don't turn while you are resetting it, at least on mine. This is a MUCH better setup, IMHO.