Ideally I'd take one of these, ammo, and food, then run for the hills

It's light
Accurate
Compact
Light ammunition, so you can carry a ton
Reasonable power, enough to kill a zombie or harvest game
50 Round magazine
Currently the best I have is this

Exact same set up but an Eotech as opposed to an Aimpoint, and no flashlight.
Pretty light
Extremely accurate
Light ammo, though not quite as light as the 5.7
30 round magazines
Decent power, enough to blow a zombies head up