Just like Talley Rings, Talley Scope Ring Base are machined from solid bar stock. The double recoil shoulder design of the Talley Base holds your scope with absolute rigidity under severe recoil. The base is checked and rechecked by Talley's quality control manager. This is to ensure the best fit possible to your firearm. This base system is required with either Talley Quick-Detachable or Talley Fixed Rings.