Huge value - Trijicon AccuPoint TR-20 3-9x40mm Rifle Scope, 1" Tube, Second Focal Plane (SFP)

Normally I stick with FFP scopes, but if you want one for a do it all tactical AR with a no battery optic. This gives you more range than a 4X ACOG (I have one of those too). Get a Burris AR PEPR mount with the Picatinny ring tops and you can mount a red dot on top with plennty of clearance of the turrets. I have a dual illminated RMR on mine and it works amazinly well with this scope. You get the best of all worlds with this combo.