the larger diam, bore in a shotgun does nothing to damper the performance of it , in fact it improves the performance by reducing recoil just as in expensive trap and sporting shotguns , over bore barrels are the thing guys pay big bucks to havethe shotgun barrel backbored to increase the diameter of the barrel , as forthe larger bore and the 45colt , if u are serious about gettin the most out of the accuracy of it , yu reload it with 454 diameter bullets,and add a scope base and low power scope, or install adjustable sights butthe rifleing has no affect on the shotgun, look at a hasting shotgun barrel they sell alsorts of different rifled shotgun barrels , even some with stright rifling to help the shot and wad stay inline with each other
ok iam done yackin ,, hahahah