bs, a 3" magnum maybe, and 382 ft lbs is a LONG ways from 500-600ft lbs, which CAN be attained by the 4" 9mm, if you know how.

The 223 softpoint does a FINE job on men, even at 100 yds, from an M4, 60 grs at 2500fps out there. The 9x23 Win can get that sort of ballistics, from a 5" barrel, at pistol fight distances, and the .45 ACP can do even better, given cut down 460 Rowland Brass, a fully supported barrel, a solid aluminum hp, bullet, with a big cnnical hollowbase and the bullet being split lengthwise, almost full length, so that it breaks into 2 pcs at impact with flesh. 2 BIG, long, sharp cornered, hard, unstable, tumbling chunks of metal, hitting the man, 35 grs each, at 2300 fps. Now that is a mean blow, yet it has no more recoil than 230 grs at 700 fps, ie, a very mild load. 60 grs at 2300 fps is 750 ft lbs, guys.
you first have to HAVE that 12 ga WITH you, and then you have to bring it into play fast enough. Neither one is all that likely, under typical conditions. The odds are 4 to 1 that you will be attacked while away from your home, not in it, and you don't take out the mail, garbage or pet, mow the lawn, or answer the door with shotgun in hand. the bad guys either bust in, giving you at most 2 seconds in which to respond, or they enter by stealth or subterfuge, and you may have less than 1 second, then.
Longarms are not securable from unauthorized use, yet ready in an instant, the way ccw'd pistols are. you have to lock up the longarms, or risk having burglars/kids get a hold of them. Leaving loaded guns lying around is the mark of a stupid, lazy, inept man.