These Winchester Model 70 Scope Mounts made by Talley Manufacturing offer a unique and simplified one-piece scope ring and base solution for Winchester Model 70 standard caliber action rifles with rear hole spacing of .860 inches. Mounts to receiver with 6-48 or 8-40 Length Screws. This simplified mounting system eliminates the possibility of an out of alignment interface or loose connection between the ring and base of traditional two-piece designs. Ultimately this provides more strength and durability than rival steel rings and bases, but with a lighter overall weight. Fully CNC machined from lightweight aircraft-grade aluminum to the industries tightest tolerances, this rigid scope mounting platform requires no lapping and is ready to go out of the box.