I'm (still) considering buying one for my 300 Ham'r AR15. I just got it, it's a beast of a caliber for an AR15!! Intended use is for hunting....probably no more than 300-400 yards. My only drawback is the reticle, need more info on it. Bushnell's website says the parallax is fixed at 100 yards. I assume the answer is no (using 1x power), but is it difficult to focus on anything < 100 yards?