Weaver Top Mount Base 29 For Marlin, Mossberg, Black - 48016 Each Weaver base is machined to the tightest tolerances for a custom fit. They are designed to fight the effects of recoil with a square-cut notch that precisely mates to the sturdy cross bolt in every Weaver detachable ring - Front Base for Browning 1895 High Wall (octagon barrel, shimming may be required for proper alignment, front base may require modification for correct fit. Gunsmith installation may be necessary) - Rear Base for Marlin Models 39A round barrel (Drilling and Tapping required)