I don't do the AR, but on my target 10/22 I'm using a Simmons White Tail Classic 6.5-20x50 w/ adjustable objective. BIG scope. Also the best $125ish you can spend on glass IF it is suitable for your needs.
I think though for a smaller lighter carbine you'd be happy wtih the Nikon offerings, esp since they have one geared towards 223 in an AR
Note that the style is available in fixed and variable powers, and that Bass Pro is really high on prices (buy from amazon, etc)
Nikon P-223 AR Rifle Scope | Bass Pro Shops