Designed to fit Winchester Model 70 standard caliber action rifles with rear hole spacing of .860 inches; American made, lightweight Alloy scope mounts; Fully CNC machined; High-grade lightweight Aircraft Aluminum; Integrated scope ring and base design; Lapping Not required; Standard calibers include but are not limited to: .223 Remington, .243 Winchester, 25-06 Remington, .264 Winchester Mag, .270 Winchester, .30-06 Springfield, .300 Winchester Mag, .308 Winchester, .338 Winchester Magnum; Includes mounting screws and wrench (6-48 Screws OR 8-40 / T-15); Sold in pairs