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TAC MOA is Redfield’s tactical reticle. This reticle has hash marks with 2 MOA increments. MOA marks makes it more comfortable in use comparing to milradian based reticles. 1 MOA is 1″ at 100 yards, 2″ at 200 yards and so on. On the other hand 1 mil is 3.6″ at 100 yards, 7.2″ at 200 yards and so on. As you can see it is much faster to do calculations using MOA based reticles.
Redfield TAC MOA reticle has 40 MOA hash marks spacing (20 MOA on both sides of the center). Then there is 20 MOA of solid line. Tips of the heavy posts is the 40 MOA.