SMR one-piece bases are machined to exact Mil. Std. 1913 specification rail dimensions. These bases are machined out of Billet 303 Stainless steel.This design allows the same scope to be used on several different rifles, always optimizing eye relief. SMR offers 0 MOA, 20 MOA, cants for Designed for right-or left-hand actions, our bases do not interfere with loading or extraction. Rails can be cerakoted to match your rifles, please call for more details.