since it is a slug barrel there is no vent rib for that style of cantilever to fit on.

are you suggesting drilling and tapping the receiver or the barrel? I don' t want the receiver drilled, don' t want to be taking the scope on and off all the time. If i drilled the barrel i would have to have a base/mount that would fit on the tapered barrel, otherwise my scope would be setting on the barrel angeled down.