The title of this thread is very misleading.
"Which Handgun for ANY Circumstance", and then we're given a set of limitations and conditions that are far from variable.
If we know in advance what we'll be exposed to, then we can choose the firearm that best fits those conditions.
Well, as the author of this thread, I have to take some exception to your charge that the title is "misleading". I deliberately left the environment of the "island" vague so as to force the choice of a handgun to be as versatile as possible. Though some assumed that the island was situated in the tropics, the location was never specified. Though Guam-sized, it isn't Guam; but like Guam it is relatively large. And, other than being uninhabited by humans (at least at the time of your solo arrival
), that's really all you know about your circumstances in advance.
The intent of the thread was to come up with the handgun most suitable to aid one to survive alone in a wild place, with arbitrary restrictions so as to strike a necessary
compromise in terms of power vs the number of rounds available for the unforseeable future. The five pound ammunition weight limitation is the diabolical part of the equation that makes a .22 rimfire a viable choice. The unknown nature, size and temperament of the wild beasts living on the Island of Gloom is the thorny factor in the equation that makes the .454 Casull a viable choice. The idea being for people to come up with the best
compromise to cope with "any circumstance" they might encounter when they are forced to fend for themselves in a very lonely and forsaken place.
The only real reasons to have a firearm along in this survival situation are for protection and/or for getting supper. Having no access to spare parts nor a gunsmith should favor a handgun that is weatherproof, simple in construction, easy to field-strip for cleaning/maintenance and utterly reliable. Though I haven't done a complete inventory of the choices made thus far, a cursory over-view suggests that a relatively disportionate number of votes were in favor of a s/s Ruger revolver (either da or sa) and the most popular caliber to be the .357 Magnum. Again, I haven't done any "official" count.
I intended this fictitious poser to require a hard choice. On the other hand, within reason, there are no "wrong" choices, as each possibility has some merit. The usual thread of this nature allows for more than one gun (yeah, I'd sure like to have a rifle or a shotgun-or both-along for the ride), plenty of spare parts on board and an unlimited access to ammunition. But then I'd have to change the name from the Island of Gloom to Fantasy Island!
Thanks to all who have contributed thus far. It's been a fun ride and, for me at least, a learning experience. More suggestions and insights are welcome!