New design one piece matte black scope base replaces the standard Weaver two slot base for Marlin center fire rifles by adding a Picatinny style rail that can accommodate, in addition to standard size scopes, red dot, hologram, compact and other short scopes. The multiple slots provide an expanded eye relief adjustment range for all scopes. Mount dimensions are 4 5/8" long and 1/2" wide at the bottom with six mounting holes in the same pattern as the standard Weaver 63B base. Mounting screws and allen wrench are included. Accepts Weaver style rings (not included). This flat bottom scope mount can also be adapted to fit muzzle loaders, octagon barrels and other flat top rifle and shotgun receivers.