Leupold AR 3-9x40mm T2
A good starting point.
http://www.leupold.com/tactical/products/scopes/mark-AR-riflescopes/mark-ar-3-9x40mm-t2/
Nice scope, but it’s pre-calibrated for bullet drop on a 55gr bullet, just like the ATN scope I have now. I’ve started loading 68gr. so I’m looking for a scope I can calibrate myself. I’ve also come to appreciate illuminated reticles for my less than perfect eyesight.