The LeupoldA(R) BackCountry series comes in cross-slot and ringmount styles that accept both Picatinny and Weaver-style rings. This cross-slot is specifically designed to fit a Nosler M21. Constructed with incredibly lightweight 7075-T6 aluminum and a milled in recoil lug and low-profile keeper screw, the BackCountry series is one of our lightest and most rugged hunting-style mounts yet. The Backcountry cross-slot mount features a 1-piece Picatinny rail base, while the low-profile rings will fit both Picatinny and Weaver-style bases. 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 pick 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.