Our 20MOA, 30MOA and 40MOA mounts were designed for long range shooting with high power optics. We recommend 20 MOA for anything where you will be shooting 800-1000 yards on a consistent basis. This will add 20", 30" or 40" of elevation at 100 yards to your scopes adjustment so you will not have to dial your elevation as much for shooting out longer distances. We reccomend at least a 200 yard zero when using any MOA mounts. For easy identification, all of our MOA mounts are marked on the bottom and side of the mount indicating the amount of MOA that is built into the base. The base is also marked with an arrow on the side opposite of the throw levers. This arrow will point forward when mounted on the firearm, towards the muzzle.