sleeper --
having a handgun caliber carbine only marginally improves your odds? How do you come to this conclusion, and compared to what? A carbine vs a handgun in the same caliber?
from Ballistics by the inch -- 9mm test
(steyr s9 vs keltec sub 2000)
FHS 147 grain, my personal favorite -- 931fps vs 1086fps or 155fps to the carbine
Corbon 125 grain +P gets you 1178fps vs 1387 fps or
209fps to the carbine
if a 5.7x28 is your preferred cartage (fiveseven pistol vs ps90 carbine)
46grain Protector III -- 1850 fps vs 1400fps -- 350 fps to the carbine
40grain Protector I -- 2092fps vs 2650fps -- 558fps to the carbine
a 30 carbine (110 grain) leaves an m1 carbine at 1990fps. It goes 1440fps from a revolver (a 7.5" barrel revolver). again advantage carbine at 550fps
So, as we would expect, you get a lot more energy from a carbine. This frequently equates to deeper penetration, but may not get you larger expansion.
from
http://www.shootingillustrated.com/index.php/6626/pistol-caliber-carbines/
Terminal Performance Comparison
Load EXP (inches) RW (grains) PEN (inches)
9 mm 124-grain Speer Pistol .71 124 13.25
9 mm 124-grain Speer Carbine .45 107 17.50
9 mm Federal 115-grain JHP(P) .57 114 14.50
9 mm Federal 115-grain JHP(C) .50 70 16.00
This is why I advocate for the heaviest round your pistol or carbine will reliably cycle. Out of the longer barrel you get more velocity but remain closer to the best performance for your ammo. The heavier ammo also will penetrate deeper since it conserves its momentum longer.
I was unable to find any specific tests comparing any 5.7x28 or 30 carbine rounds from a pistol vs carbine. I would venture to guess (I hate guessing) that since both the 30 carbine and 5.7x28 were designed first as carbine rounds they will perform well from their respective platforms.
back to the point, since I can ramble. A carbine offers many advantages compared to a pistol -- longer sight radius, electronic sights if you desire, larger ammunition capacities, easier to train and become proficient with. The only drawback is the larger size may limit usability with one hand.
Your premise that we are preparing for a zombie hoard is a false one. The simple truth is that a carbine is a more effective tool for incapacitating an attacker than a pistol is. Because of this, given the option to choose, I would pick my ps90 over my walther PPS for a firefight. In the context of this thread, I would choose my ps90 over a ruger 10/22.