Henry Big Boy (2nd Generation) Receiver Scope Mount BB-RSM To optimize accuracy, Henry Scope Mounts are available for all Henry H004 series Golden Boy and H006 series Big Boy models. Each of these rifles now come drilled and tapped for easy scope mount installation. Current production (2nd generation) Big Boys are drilled and tapped on the top of the receiver. Instructions on installation of the scope mounts is provided in the packaging. All Henry Scope Mounts accept Weaver style detachable 1 top mount rings (rings not included). To determine which generation of Big Boy you have refer to the serial number table provided so you select the correct mount. Instructions on installation of the scope mounts is provided in the packaging. All Henry Scope Mounts accept Weaver style detachable 1 top mount rings (rings not included). Note to Big Boy owners In September 2011 Henry Repeating Arms began shipping the 2nd generation Big Boy rifles which feature receivers that are drilled and tapped for the scope mount. In previous production 1st generation the barrels were drilled and tapped if rollmarked Bayonne NJ. First generation Big Boys use the BB-CSM Cantilever Scope Mount. 2nd generation current production use the new style BB-RSM Receiver Scope Mount. 2nd generation Big Boys start with the following serial numbers: H006 = BB0047222 H006M = BB0015530M H006C = BB0021188C