I would be better off with boarding up in a mall with a few allies of mine to help defend the place. We would use what we found in the mall Dawn of the Dead style and defend ourselves that way. Assuming this is just the crumbling of society and not nuclear apocalypse, we would grow our own food, and a lot of it. We'd basically re-create our own, new, sane society and try to build our way to the top. We could keep to ourselves and build and build our society until it's finally just too big to fit in the mall and we just open our doors and expand our empire.
HK-94 though. I'd always need a fast, reliable way to take out any mutineers.