If a pump-action gun is to be used as a dedicated slugger, which is the more DURABLE option for scope mounting, cantilever barrell or a bolt on sideplate??

Simple question I hope.

If it makes a difference to anyone, the scope WILL not have a magnification over 4x, if even that much.

I'll save the MFR. debates for another time...(btw, I've already decided)
Also, please don't suggest a combo gun, or any dis/advantages ofa comboin relation to my question. The barrell ain't coming off except for major cleaning, end of season. I've got enough shotguns already,but this would be the first one with a scope.