I have a dedicated iron sight AR, and a heavy barrel .223 AR with a 6x20 scope. I wanted this gun, a Bushmaster M4, to be an all around AR. I went with a Burris FF 2x7 scope in Burris Tac. rings. I used 1/2 inch Bushmaster risers, and Medium height rings. I used a top half to the rear ring with a built in pickatinny rail. Mounted a Burris Fastfire ll holographic red dot sight to it.
The system works great. A proper cheek weld on the stock gives good allignment with the scope. A slight raise of the head gives a good view of the holographic sight. Along with the Streamlight flashlight on the front, this rig is good from accross the room to 500 yards. Its a neat rig that works well.
Larry