TEOTWAWKI is the acronym for "The End of the World as we Know It"(Spoken as "Tee-ought-walk-ee" and 'Tee-oh-tee-whacky"). This scenario can be brought about by any number of apocalypses including massive urban riots, global warming, revolution/civil war, extended droughts, invasion, nuclear exchange, global pandemic, aliens (up to the reader to decide which kind), comets, EMP, zombies, hippies, bigfoot uprisings, giant radioactive ants, Nazis from secret moon bases...the list goes on and on. While some of these may be more likely than others, all could leave you in need of a good handgun.
There are several underlying fundamental qualities you will want to have in your universal go-to handgun for when everything goes to pieces.
1. Avoid exotic designs. What you want is a design that is simple, reliable, and has been around the block enough to have all the bugs worked out. The Taurus Judge is a neat design, but does it have the same real world reliability testing as a Smith K-frame?
2. Mass production is mass availability. Look for a design that has been produced in great numbers, preferably by several different manufacturers over decades. This will ensure that there are many spare parts, magazines, et al are out there both now and hopefully later. Good luck finding a replacement slide stop for a Heckler and Koch P7M13 after the zombies walk.
3. Look for a platform designed for a common and effective multipurpose caliber. Good examples of these are 38/357, 9mm Parabellum, and 45ACP. Incidentally, a number of manufacturers also markets all three of these rounds in companion pistol caliber carbines. This enabled you to be able to stock up and increases the chance that if you can come across any ammunition in the future, you may be able to use it. While 500S&W, 45GAP, and .357SIG are white hot and super cool, if they are hard to find now; how about when the fit hits the shan?
Of course, your mileage may vary, but taking the three points above into account, here is what I would personally come up with.
The K Frame Smith
Ahhh, the good old K frame has been around for slightly over a hundred years, just barely beating the Colt 1911 in age by about six years. These hard-hitting, reliable firearms have been used by almost every western military and police force on the planet at one time or another. They include the models 10, 13, 19, 65, 66, 67, and others. It is estimated that just Smith alone has manufactured more than 2-million of these guns. The fact that most of these models are in 357 enables you to fire cheaper 38 lead heads and wad cutters for practice and increases your chances of being able to find replacement ammunition. This country simple design can be repaired easily and taught to a new user in no time.
The Colt 1911
John Moses Browning's most loved son is on this list for a number of reasons. Scores of both large and small companies have produced 1911's in great quantities. Odds are if you run into a semi-auto in the wild in the US, it may be some sort of 1911 variant, they are just that plentiful. This makes the parts, magazines, and knowledge to repair them all the more common. It's hard to find a caliber that hits harder than 45ACP but be sure to stock up on reloading supplies and save your brass, you may need it.
The Browning HP
The Browning GP35, commonly known as the Hi-Power is probably one of the most well respected handguns of the world war two era around the world. Many surplus Inglis models are floating around the country as well as Argentine FMs, Belgian FNs, Browning Hi-Powers, and several near clones like the FEG and Charles Daly Hi Power. Many militaries around the world still carry it as an issue weapon. The fact that their 13-round magazines are also common and easy to find and the firearm is an improvement on the 1911 design puts them in good favor. Their 9mm cartridge is one of the most inexpensive around and is available currently in great variety.
The Beretta M9/92 series
Often reviled in gun circles by true 1911 believers and military personnel who have encountered lowest-bidder magazines in high-stress situations, the Beretta 92 has an undeserved bad rap. Yes, the grip is a little beefy. Yes, the slide exposes most of the barrel and I personally don't like that. However the Beretta 92F survived exposure to temperatures from -40 to 140 F (-40 to 60 C), being soaked in salt water, being dropped repeatedly on concrete, and being buried in sand, mud and snow. Additionally, the 92F proved a MRBF (mean rounds before failure) of 35,000 rounds. Several million have been produced and they are still (like it or not) the standard US military sidearm as well as still in use with several LE departments like the LASD. They meet all three rules and make the list.
The Glock 17 and 21
Since 1982, the name Glock has become synonymous with reliability. Once derided as combat Tupperware, they have found a following and are often seen in police and personal defense use. The 9mm (model 17) and 45ACP (model 21) versions have always been popular sellers and more than a million have been produced and sold. Spare parts are inexpensive and Glock Armorer courses are spread everywhere that can turn you into a Zen master of repairing your personal plastic. Although mid-sized and compact versions are available, the use of the standard full sized models is recommended due to spare parts/magazine availability et al.
Of course your own personal choice may vary, just keep the three rules in mind. Please feel free to share your own TEOTWAKI handgun selection in the comments below.