This is my favorite level 0 weapon in the game. But it's a combo card. With the right investigator and team, this is enough damage to last for some time, and you can spend your XP on other nonsense (more likely on other cards to make sure this one works). Since you're looking for positive or 0 tokens, you don't need to worry too much about increasing your number either. Is this build as good as set-it-and-go weapons like the .45 Thompson or the Cyclopean Hammer? Probably not. But it sure is FUN.
As other reviews have pointed out, this is really only viable on taboo with tokens, or maybe Jim who is all in on fishing for skulls. With enough tokens in the bag, you don't HAVE to guarantee drawing those tokens, it's okay to pull and try to get lucky every now and then, but you really need to play some other cards to help you draw that non-negative token, ideally more than once a turn on 3-4 player:
- Olive McBride is essential. You'll need to resolve two tokens, but if one is non-negative you'll likely pass. And if you fail, not a huge loss.
- Nkosi Mabati is very helpful, too, if you've named or for Jim. Even better, someone ELSE on your team can run him, and trigger his ability, saving you from taking Charisma for Olive's spot
- "Eat lead!" -- I don't recommend this card. You need the ammo.
- Grotesque Statue, good, but take up a handslot.
- "Hit me!" -- this is excellent because you can play it AFTER you've revealed a token. So it'll sit in your hand until necessary.
- Favor of the Sun -- congratulations, you found a non-negative token!
I really like Zoey Samaras for this build since she can take all of the above cards, and also Contraband to get a ridiculous number of ammo on the gun. With the -token build, she should also take Sacred Covenant and Blessing of Isis to keep the in the bag and turn some of them into her , to deal 4 damage with one shot. It's a chunk of deck space to try to make this work, so hopefully you can leave the generation to someone else on the team, but this is absolutely effective on higher player counts.