Integration offers strength and consistency. Browning&';s Integrated Scope Mount System unitizes the ring and base into a single, ultra-rigid unit. Machined from 7000 series aluminum alloy, they eliminate alignment problems and the possibility of a loose connection between the base and ring. Machined from 7000 series aluminum for high strength and durability Integrated design eliminates alignment problems and the possibility of a loose connection between bases and rings .500 in Medium height for scopes up to a 50mm objective with a standard barrel contour This system is only compatible with BAR and BLR rifles.