As soon as we have them "figured out" they change. I shot a 125+ pound boar, at 15-feet, last Sunday night, in the headlights of the truck, on a narrow dirt roadway, hemmed in by trees and vegetation on both sides of the truck almost up to the F350 mirrors. The 60+ pound "Junior" pig that I did not shoot with the 223 Handi-rifle (single shot) made a bee line toward me. He was on me before I knew it and with not many choices for places for me to go, I climbed up, onto the expanded metal game carrier. I do not know and am surprised why the pig didn't get me, gnashing its teeth, grunting, scared, adrenaline flowing.
I could not have stopped that charge with a lever gun or bolt rifle. Absolutely not with a Handi-rifle. Pump shotgun - yes. Handgun revolver or semi-auto maybe if the instantaneous shot placement was very good. My adrenaline was pumping - after the charge, but flowing none-the-less while shooting the bigger boar at that close distance, at night, by myself, way back in the woods. I was lucky. Nothing bad happened to me.
Until you have "been there", you don't know how you will react...daylight changes things very little when under duress. I think the 12 ga. pump or semi-auto shotgun, short barrel, riot gun variety, 5-shots, #4 buck shot, would be enough. At that point, you are not hunting to eat the game, you are shooting to save your own skin.