Leupold BackCountry cross-slot bases are made of 7075-T6 aluminum, making them some of the lightest and most rugged mounts yet. This BackCountry cross-slot base is designed to fit a Remington 783 Long Action and accepts both Picatinny- and Weaver-style rings. The mounts are every bit as rugged and dependable as the Leupold optics they secure.