There was one shooter here, a few years ago, that had real problems with shells sticking in the chamber, and used brute force to "unstick" the empties. I can't remember for sure (no coffee!) but I think they whacked the stock downward on a hard surface, while grabbing the slide (which works on an AR-15/M-16/M-4 platform). My memory's off on the method, could have involved a hammer... At any rate - and the point of my post - is that they wailed and complained bitterly, when the brute force _method-du-jour_ broke or badly bent the bolt carrier. Then there was a big commotion on how the bolt carrier is a bad design, how it needs redesign, etc etc., all of which is nonsense. We do see an occasional broken carrier, just as most any part can break, and they usually break at one of the forward welds. All that being said: A smooth chamber is a happy chamber, and a happy chamber is a happy KSG.
If you've not already done so, have a gander at your chamber, and if it looks sort of micro-bumpy in there, or even looks like a matte finish (like the outside of the KSG), a little fluff'n'buff there might be something to bring it to unfailing 100 percent reliability, and possibly avoid brute force breakage of parts.
And for the record - clearing a stuck (FIRED) shell would be better off done with a stout rod down the barrel, a very light hammer giving tappity-tappity hits while pulling back the slide. Never heard of an UNFIRED shell getting stuck, but if that happens... then the only safe way is the butt on hard surface method, with muzzle pointed safely away from anything you don't want to make holes in.