most AR15 dont shoot 55grn ammo very well. most are designed around the heavier 68grn bullets. the leupold AR scopes are bdc set for 55grn bullets kinda odd choice for most current production AR15's.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith