I have a 'like new' Burris Scout scope on my Cav 15. My rifle has standard Hand Gaurds and If I use the 'nose to charging handle' shooting position the Yankee Hill extension on the flat top is not quite long enough to get me the 10" eye relief this scope is designed for. It would work perfect on a rifle with a rail on top of the hand gaurd. If I could trade it for the right 1-4 paower scope or sell it for enough to get one I would. If anyone is interested let me know.