The AR-50 is another beast all together, unless Armalite has changed the cheekrest on the rifle, you'll have to do one of two things. The top edge of the cheekrest will hit the bolt handle if you adjust the cheekrest down to far when adjusting for scope alignment. So if Armalite hasn't done this for newer rifles you'll have to cut about 1/4" off the side or buy super high rings So that everything clears.
You would think that after all these years, Armalite would've done this mod to all the newer rifles leaving the shop. Maybe they'll read this and start doing it on all the new rifles being built. I have about 1/2" or more under the Bell of my scope and it has à 56mm bell. I suppose I could modify it myself but haven't had the time or felt like having to redo everything once I mod it. Something to think about before buying your rings, mod it first and the buy rings that will get it closer to the bore.