I had an IOR 4x tactical type scope on one of my AR15s for a while. It had nice glass and looked pretty sturdy. I could be wrong, but I thought the eye relief was a little finicky, but I seem to have more problems with that than most people. A fair number of the guys I shoot with have used IORs and everyone seems to eventually sell them, not sure why. I'm no scope expert, but personally I'd get a Leupold