This topic has already been touched on in this post – Best Pistol Caliber for a Survivalist. But I wanted to touch on it again.
When picking the caliber for a survival situation, several factors should be considered:
Effective stopping power – how effective is the caliber against a given target. The 22 long rifle is great on small game, but terrible on grizzly bear. So use a caliber that is appropriate for the target.
Recoil – how much recoil does the caliber have? Try to pick something that most members of the family can shoot. There are people out there that will buy a 454 casull with no thought to how well their 14 year old daughter can shoot the pistol.
Price – how much does a box of ammo cost? Its not cost effective to buy some odd-ball caliber that cost $30 for a box of 50 rounds – not when you can get other calibers for a lot cheaper.
Pistol and Carbine – does the caliber have a pistol and carbine rifle option? Lets take the 357 magnum for example. There are lots of pistols for the 357, and several rifles, like the Marlin 1894 and the Henry Big Boy.