Nikon P-223 3-9×40

Nikon makes quality glass, for all types of applications. Their scopes are well-regarded in the community, and the P223 line was designed specifically for the AR crowd. It's got a BDC reticle, meant for 55gr rounds, and it doesn't have an adjustable objective, nor is it a first focal plane scope. It is, however, a very clear, well-lit long range scope that's great at the range for not a lot of money. And that counts for a lot.