it will need to be drilled & tapped to mount a scope.

 

Wondering if the spent shell will have room to clear a scope if one mounted? Have never seen a scope on bolt shotgun- only in scoped rifle.

 

Marlin 512, Savage 220 and 212, Mossberg 695, and the Browning A Bolt slug gun are all bolt action slug guns that take scopes. The Savages are still in production and will probably shoot circles around an old bolt action that you drill and tap to mount a scope.

 

I think you will need a side mounted scope base. Should be enough of metal to the left of the ejection port to drill and tap.