In an aluminum barrel with a receiver that is primarily plastic sheathed/shielded by thin aluminum, even a low velocity shotgun shell would cause the barrel to either crack, peel like a banana, and/or blow up in your face.

That's REALITY for even the Navy MK V.

The cool thing about the Navy MK V is that it was the first sidearm I carried on a Boarding Team (as the Signalman) along with a Riot Shotgun. The GI issued holster allows for about 3" of the (10 ga) barrel to stick out the bottom. The sailors onboard the boats that we were boarding were often amazed at what kind of "Hand Cannon" was it that I was packing, beside the shotgun.