A very secure choice. These are all steel bases for use with Winchester Model 70 steel rings on Model 70 rifles. Like Winchester rings, these Scope Ring Bases are machined from solid bar stock. The double recoil shoulder design of the Base holds your scope with absolute rigidity under severe recoil. The base is checked and rechecked by quality control. This is to ensure the best fit possible to your firearm. This base system is required with either Winchester/Talley Quick-Detachable or Winchester/Talley Fixed Rings.