In short, no.
There's probably a dozen things you NEED to survive (and the skill to use them) before you'll need a gun. Surviving is a LOT of hard work, and not much Rambo.
Hell, with the hurricanes over the summer and no power, a lot of people were suprised at how much work just day to day living is, when you have to hand wash your clothes, start a grill or fire to cook (any idea how many people howled when they were told to boild their water before consuming -- because they didn't know they could boil water on their GRILL?). Sure Mr Nomad is going to run around with no personal hygeine, and be infested with parasites, have his clothes rotting off of him, be completely demoralized, have little to no hope of people helping him because he'd be such a health risk just to have around.
That is, if the cold doesn't kill him first.