Red dot sight range?

[BRL]

I inherited a Bushmaster AR (.223) with a red dot sight on it as well as a Beretta CX4 Storm in 9mm with a red dot sight. What are the ranges expected for red dot sights? Obviously, the main concern is the AR. What range should I sight it in for? Am I limiting my distance with that sight? Should I replace it with a scope of higher power and use the red dot on a .44 mag rifle or handgun?

Thanks!!

[poncaguy]

I sighted my AR 223 at 100 with the red dot..................