20mm shells pack enough explosive to down jet planes. cut off .50 bmg cases where they start to bottleneck and they are a perfect fit for 10 ga. develope a 10 rd box mag and you'll have something (along with another idea already proven to work with 12 ga),
I wonder if an adaptation of the VEPR/Catamount Fury/Saiga based shotguns is doable? Could a rifled barrel be made up to work with these cut down cases? Admittedly, they'd no longer be " shotguns", but THIS is an idea that interests me.