Yeah, preparing for the Zombie Apocalypse is not as straightforward as it seems. Hmm, personally I would consider a couple of factors:
- Low probability weapon jamming in "all weather" conditions
- Light weight/bulk of ammo
- Availability of ammo, which starts becoming an issue a couple months
Stopping power is another interesting factor. It seems tempting to pick a weapon chambered for a 5.7x28mm like a PS90 because the only way to "stop" a zombie is to put one in the brain (and their heads are pretty soft from necrosis) and you can carry a lot more 5.7x28 than 5.56x45s.
Hmm, but then it occurs to me you could have an AR five seven and have already thought of this!