Though it's a little afield of JordanHeezy's original post, lethality in .22 is a matter of some debate. If he wants something for the veritable SHTF moment, then I suggest he supplement his Mossberg with a good .22 Magnum-firing weapon and lay in a supply of something like Hornaday's .22 WMR 45 grain FTX. There are many rifles that are made for this round in bolt, lever and semi-auto configuration (I would prefer the Henry because I like lever-guns, but that's me). In hand guns, revolvers seem to be the way to go; I haven't heard of any autos in WMR but there probably are some. Ruger, Smith & Wesson, Colt's and Charter are some names to consider. A well-handled .22 can indeed be deadly WITHIN IT'S INHERENT LIMITS. In other words, a Barrett can kill at .22 caliber ranges or at .50 caliber ranges, but even the best .22 cannot be lethal at Barrett ranges (it's more of a "Did you hear something?" to those targets). Learn your Mossy and grow into the sport, because outside of Basic Training (Boot Camp to you Jarheads), there is no quick way to learn riflery or marksmanship (and, no, Call of Duty for XBox does not count!).
"History teaches that war begins when nations believe that the price of aggression is cheap." - Ronald Reagan