i own an ar and to tell you the truth a scope is nice but those iron sights are good out to 200 yards for small target shooting (pie plate size). i wear glasses and love my scope but in the service i was trained on open sights and given a sturdy rest the .223 is a nice, easy to shoot round. a little practice and you could easily hit plates at 200 yrds with an ar. ammos cheap so don't worry about getting a scope before you start to break-her-in
you never know open sights might be the thing for you. to this day i'm a lot quicker on target with open sights than with any scope or red dot for that matter.