The one gun that is planned on being relied on if the 'SHTF'. Although the choice of weapon for this purpose is highly personal, most will select a robust rifle (or shotgun, especially in an urban
environment) of proven ability under adverse conditions. Most
importantly, it will be a weapon with which the owner is very familiar.
Virtually all gun owners will, if pressed, admit that they have designated one of their arms as the 'shtf'gun.