Weaver Mounts 63BS Top Mount Base 1-Piece Silver Aluminum - Marlin 36/336/Mossberg 640

The Weaver Mounts 63BS Top Mount Base is a one-piece scope base machined from aluminum and finished in silver. Part of Weaver's classic Top Mount Base line, this 1-piece base is engineered to give a rifle's receiver a rock-solid, optics-ready mounting platform.

Machined to tight tolerances for a custom fit, the 63BS features the signature Weaver cross-lock design that lets rings seat firmly and hold tight under recoil, giving a scope a stable and repeatable zero. The silver finish blends cleanly with blued and stainless receivers alike.

The 63BS is specifically profiled to top-mount directly to the receiver of the Marlin 36, Marlin 336, and Mossberg 640 rifles. Mounting screws are included with the base. Rings are not included and are required to install a scope.