Hm, this seems to be the general consensus. Only thing is, I'm worried about short-stroking it at a moment of crisis. I hope I won't get laughed at, but is a double barrel or a single shot shotgun a viable self-defense tool? I mean, I live in a tiny apartment and all...
IMO anyway, short stroking is a bigger concern than most people make it out to be, if you don't get that much practice. You're probably going to revert to your level of training under stress, just a biological fact.
Dead police officers have been found with spent shells in their pockets (even after most departments switched to automatics) because they always saved their empties at the range (though newer training has addressed this).
In that one Miami Vice movie (I think), they had a competition shooter playing the bad guy, and he did a quick draw and killed a guard. Immediately after, he looked left and right, dropped the magazine, and cleared his gun exactly like he would in competition, even though that wasn't in the script (and that take made it into the final cut, because the director liked it). Just the stress of being on a movie set, with no real bullets flying anywhere, made him revert to the training he always did.
If you're worried about pumping the gun, there's nothing wrong with a double, especially if you can find a single trigger, hammerless, non-selective, non-clockwork, non-auto-safety gun in your price range. One of the simplest possible guns to use. Keep the safety on fire, with the gun broken open, with shells in. Practice closing the gun, mounting it safely (finger off the trigger), aquire target, aim, fire.
With a pump, there's no substitute for practice. Dry practice can help a lot, but if you live in a small apartment, you're not going to be able to do that at home. Pumps should be run
hard if you want reliability, and your neighbors won't appreciate a loud, repeated "SHUCK-SHUCK!" noise.
Pistol caliber carbines are also a great choice. An auto shotgun would be good, but you're unlikely to find a shorter barreled model in your price range.