I've never had to take a dangerous game animal yet, but the time may come. I work in the logging industry and with the increase in Black Bear and Cougar in our area, the peaceful encounters may become nasty before long. I spend a lot of time walking in the woods looking at jobs, all alone. It's just a matter of time. There's getting to be a bear behind every tree around here and the cats are losing their fear of people since they outlawed hound hunting. Had a cat giving me a look-see a month ago. As soon as I saw it, it took off. Makes the hair on the back of your neck stand up!
Oh, I carry a cut-down Marlin 1895SS ( Wild West Guns Co-pilot) in 45-70 with either some 405 gr Kodiak Flat point FMJ solids or Garrett's 530 grain hammerheads. Either will shoot through any living thing and leave a BIG hole doing it. I carry it in a Nimrod back-pack scabbard. Really works slick. Sometimes I'll carry a Marlin .44 carbine or occassionly a 1911. Mostly the 45-70.
Zorro is entirely correct on one thing. The most dangerous thing a person is likely to come up against is a pack of feral dogs. It's the only thing that ever "treed" me. Kept me there for 45 minutes. Never left the truck without a gun after that.