Nightforce one-piece bases are machined to exact Mil-Std. 1913 specification rail dimensions, assuring perfect alignment. This design allows the same scope to be used on several different rifles, always optimizing eye relief. Choose from 20MOA or 40MOA tapers (40MOA for Remington actions only). Designed and machined for right- or left- handed actions, Nightforce bases will never interfere with loading or extraction. A168 - Fits Round Receivers Mfg: Nightforce SPECS: Win SA base does not fit WSM Models.