In the "Zombie Ammuntion" thread, I waxed on about what my perfect zombie gun would be; a week ago, I thought it would be a box-magazine-fed, slide-action .30 Carbine. But that was before I SAW THE LIGHT. And the LIGHT did shine upon my face, and the DARKNESS was lifted, and the LIGHT was in the form of this.
Available as a bare upper receiver, all the rail-space a fella could want for mounting lights and sights and pointy stabby things, American-made and actually affordable. Chambered for the 5.7x28mm cartridge, which betters the .22WMR by a good margin-- it's essentially a modern .22 Hornet. 50-round magazines are standard, and best of all, it has ammunition and magazine commonality with a very good sidearm, the FN P-90.
So here we have a package that packs light, shoots reliable -the AR-57 is a straight blowback design-, is quite accurate, has plenty of punch out to reasonable range, and with full mags in your rifle and both sidearms (you really need two) you've got 90 rounds available before you need to change a magazine. The only fly in the ointment is that ammo is a little on the spendy side, but I've got to believe after the Zombie Apocalypse, money isn't going to matter much.
I'm still going to want a good shortsword for when things get real down and dirty-- and did you know that using an adjustable cup from a bottom bracket, you can screw two freewheels together to make something that very closely resembles a flail head?
For that matter, I can't believe I'm the only one who's ever hefted a drive-side crank and thought, "Hmmmmm..." Although I'd want to bolt it to a hatchet handle, and use a steel ring for strength. This might just be the best use for leftover cottered cranks, come to think of it!