It is accurate with iron sights at 100 ft, but would probably be relatively accurate way beyond that with the right scope.
Since, if Trump gets elected and pulls our fat out of the fire, my AR will never be needed, I hate to spend much on a scope.
Of course, the last time I went to the range, I spent $60 in ammo in about 15 minutes.
Luckily, prices have come down.
Vortex makes a nice red dot sight, too - the Strikefire II. Not as compact (or pricey) as the stuff from Aimpoint, but they work well.
general thinking is that you want your AR to own everything inside 300 yards. My thinking is that I want my AR capable of performing surgery anywhere inside of 300 yards.