45 Colt and then only in an FA, Ruger Blackhawk, or Redhawk. It can easily be down loaded and,with Ruger-only level loads, it can handle big game under the right circumstances. If you take the African Big Three and hippo out of it, it can handle the rest nicely.
Honestly I would choose one of the Linebaughs, but they are not on the list. Probably the 500.
In retirement, my arsenal was trimmed down to just .22LR and .45 Colt.
I have 4 Mark IIs, a Single-Six and an SR22 in my .22LR set and a 1971 Blackhawk Convertible (UNconverted lockwork), a Lipsey's Flattop New Model Blackhawk Convertible and a New Vaquero in my .45 Colt set. The Lipsey's is my home defense gun, but I'm not afraid to back it up with any of the semi-auto rimfires.
The Peoples Republic of New Jersey did force me to add a Security-380 to the arsenal for CCW (the rimfires weren't allowed and the Lipsey's .45 is too big).
I'd have to choose 9mm because it is the most popular and thus most likely to be able to get ammo for.
My preference if I felt I was going to need one for protection would be 357 Sig (which by the way the OP did not even list as a choice) followed by 45acp.
Hard to choose. 22/22WMR or 44, or .45. In the end I went with the .22/.22WMR. It's what I shoot the most and enjoy shooting the most. I love my .44 SPCL, and my .44 Mags, so that would be a close second. But if I didn't reload, ammo costs would severely limit the fun. Same with the .45.
Plus, with .22 shorts you can get away without hearing protection for a few shots…and about 30% of my firearms are .22 caliber
Well, I wondered what was the fan favorite. Now I know. .357/.38 Spl. tops the list, followed by .22LR/Mag. .44 Mag and .45 acp tied for third place. I like all those choices. Thanks to all that participated.
The poll was limited to 10 options. I picked what I think are the most common/popular ones, not necessarily the best-performing ones. There are dozens of cartridges that I didn't list.
I chose the.22 lr if it's the only one I can have. Accuracy, ammunition availability and personnel knowledge, from poachers, that bear, deer and hog are regularly taken with one shot.
Now that's a tuff question. The .22LR, .44mag, and .45 ACP are all my favorite handgun rounds, and they all have their purpose and serve it well. Can't pick just one.
I will say though, for general self defense carry from the two legged creature kind, I would prefer the .45