That's an awfully big scope to put on an AR-15. But IOR scopes have Schott glass which is German glass owned by Zeiss. I had a IOR 2.5x10x42mm and it was very good. But I needed more power so now I have a Weaver Tactical 3x15x50mm and that scope is very close to the quality of my New Zeiss HD5. The IOR isn't a $1,000 dollars better then the Weaver. The SWFA 5x20x50mm FFP is very good at $1500 bucks.