TexasCHLforum.com

In regards to rifles firing 5.56mm/.223 (ARs and the like), I zero irons at 50 yards. The trajectory is almost flat out to 175 yards with common ammunition types/weights for the caliber. Generically speaking (yes, I know that bullets don't actually go up unless the rifle is fired in an elevated fashion), the greatest bullet "rise and fall" above/below the zero line is just over half an inch across that distance with 55 grain ammo, and just over an inch drop with 62 grain. If I needed to reach out further than that, I have other rifles in larger calibers that can do a better job at longer ranges, with optics on them. I will add a link to a ballistic trajectory calculator and you can graph it for yourselves.

http://gundata.org/ballistic-calculator/