Two M223's and a P series AR mount from Nikon.
The M223XR mount with +20moa allows you to have your scope adjustment near center when zeroed for longer range. If you plan on shooting to 600yds it's nice to have. The XR is a rock solid mount, been sing one for two years.
The only negative about the M223 is it is not a QD. It requires a allen wrench to remove. If you don't care about QD then it's not a negative.