Complicated question, which has stumped us Daniel!
Though I used to like guns just like you, I think I have come realise that they are pretty awful things. Especially when in the wrong hands.
If we absolutely had to have guns I would go with something that only affected machines and did not hurt animals like us.
Actually, I take that answer back! The best, biggest and most powerful gun in the whole world is in Switzerland and France: The Large Hadron Collider! It doesn’t shoot bullets but fires tiny particles around in a circle 27km long to hit each other, and it’s how we have discovered so many cool things about our universe already! And they’ve only been working it for a couple of years! It goes to show that with all the money we spend on making guns and tanks and jets, we can be doing other much more useful things. And when we work together to do these, it’s all the better!