You can only have one gun.....

Nice Gun Collection
Nice Gun Collection
This is kind of like the old you're stranded on a desert island thing except we want to know what gun you would choose if you could only have one for the rest of your life. I know that’s a really frightening scenario for most of my fellow gun nuts but it's only for fun.

   To make it even more fun that one gun can be any gun in the world, no price limit. So what would you choose? Bear in mind that this would be the only gun you could EVER have or use so it would have be good for whatever sporting activities you enjoy.

   And of course for all you preppers it would have to get you through any forthcoming apocalypse or commie inbred mutant zombie invasion. Please give us your choice and reason in the comment box below, and please be specific.
Let the debate begin!