Just to be clear, Im am not saying dont carry a backup, just that when it all hits the fan the odds are against you; and any firearm or ammo can have a failure to fire, especially when cold (cold parts do break, its happened to me twice).
And critters 'make their living' out there; most of us dont. We are in their element to start with (point, critters). A fatally wounded Cape Buff will do a death dance on you before he dies; a bear will tear tear you up and may or may not eat you (another point, critters). A human will often become conscious of his wound(s) and swoon (another point critters). The math says that, even though armed, a big, dangerous animal, especially a peditor (and I include some humans in that) will have several points on us if he's hunting us and we are suprised.
FWIW, I have stood face to face with a bear in the wild at about 10-12 feet. We both lived. I consider it one of the most significant events of my life.
Thanx Bear!