Ahh, see I live in New Zealand so we don't have bears or any large predators really but we do have possums with a P and I've had many a run in with the furry kind. Best course of action is to grab them by the tail and swing them around although these possums are the size of a cat and not a person.

Should I ever venture into bear territory I'll make sure to take a paintball gun with me.

As someone who owns a nail gun, I am grateful for this safety mechanism but holy crap, my one is rated for hardwood and packs a hell of a punch. If it didn't have the mechanism it could be a deadly weapon, especially in close range. I get so stressed when I see people modify them o remove that mechanism because it can end very badly.

Spud gun gets my vote!

Nail guns aren't a ranged weapon though, you need to press them against a surface to engage the firing mechanism. If they're not pressed up against something hard, the trigger won't work.

Paintball gun with frozen paintballs hurt like a mofo and would work well but make a mess.

Spud gun is another option.

That or a hose. Drench them. Possums HATE getting wet.