Cross bow its excellent - Vortex Viper XBR 2.5-10x44mm Crossbow Scope w/ Illuminated XBR-1 MOA Reticle, Black VXBR-1

I put this on a Barnett Vengence, if you can afford it its great. I used the 2 inch Vortex Cantilever AR Mount. It gives perfect eye relief. I also added the objective clamp it makes it easier to adjust. This is my first Vortex. So far so good. Enjoy. I look forward to killing a moose next year with the setup.