Leupold BackCountry cross-slot bases are made of 7075-T6 aluminum, making them some of our lightest and most rugged mounts yet. This BackCountry cross-slot base is designed to fit a Marlin 336 and accepts both Picatinny- and Weaver-style rings. Nothing is more crucial than the link between your scope and firearm. That's why our mounts are every bit as rugged and dependable as the Leupold optics they secure. And with a huge variety of mounting systems to choose from, you're sure to find the perfect match for your firearm and style of shooting. Made in the USA and guaranteed to hold up to a lifetime of abuse, Leupold mounts will never let you down.