I have a buckmaster and have been quite pleased. While it is only on a .223, I still think a Nikon (or any other reputable brand) will handle everything fine. Mine bounces around in a tractor or on a 4-wheeler continuously, has been dropped a couple times (once on concrete), exposed to the worst mother nature has had to offer, and it is still dead on every time. If a buckmaster can survive me, then a monarch should survive anybody.