Some of us (all fingers pointing at me) have vision problems that preclude us from using irons anymore. I can't see the front sight at all without my glasses--and with my glasses, I can't see the target.
I tried with irons at my last AS and the best I could do was a 161.
Later in the day, I swapped out to a scoped rifle and cranked out back-to-back Distinguished scores of 241 and 242.
Getting old kinda sucks