Weaver makes a base with the number 3A, part number 48403. It is a side mount base (requires the ring portion to work). It is for several lever guns including Winchester 53,55,54,65,66,71,1886,1892,95 . The side mounting ring portion is 1" High part #49340 and 1" Long High part no 49340. This mounts are typically used with top eject lever gun to off set the scope to the side to prevent interference with ejected casings. Phil.