I take it you have a .22 WMR based on your screen name. Don't underestimate the .22 Mag especially in the Hornady 30gr V-Max bullets going 2200 fps. I have a Ruger 10/22M with a magnum research carbon fiber barrel. I guarantee it would stop or slow down an intruder. Put 10 of those puppies in a zombie and it'll give you an excellent advantage over the undead. Then you can use your scrapyard to finish them off.
How do those stats stack up with the 5.7x28mm? Seems like if they are even close the .22 mag might be a better value.
Getting my Zombie kit ready and watching out for those Corpse Men!!!