The scope base / picatinny rail is where you will probably find about the most choices. I picked up the Nightforce X-Treme Duty One Piece Steel Base with a built in 20 MOA cant to maximize the elevation adjustment in my scope. This base is heavy, solid, and has a built in recoil lug. “The integral recoil lug is machined on the bottom of the base and provides a precise fit when bedded to rifle actions, preventing any movement of the base or recoil stress on screws holding the base to the receiver.” A reason for a steel base vs. an aluminum is for strength and to alleviate torque on your scope under recoil. If you watch rifles shooting in slow motion you can see actions twisting and barrels whipping. For this reason I will never use 2 piece bases. Your scope will end up taking the brunt of that twisting force. The steel base as opposed to the more flexible aluminum base also helps in this area.
