LogFAQs > #975759413

What kind of gun?
Typical hand gun or rifle?
Going to assume the infinite ammo cheat code isn't on.

Depends on distance and availability of cover. Inexperienced moron w/ a regular gun and no reloads could easily waste all the ammo firing when the katana user is distant and going between cover. If he runs out of bullets, he's fucked. That's how it would go down w/ the katana user winning.

Honestly, daggers/knives would be a far more useful weapon vs. a gun. You can throw them if gun dude is being careless and not using cover himself, and the shorter range will actually be a boon if it's a dense urban environment and you can close in. When you're in basically grappling range, he's gonna have a lot of trouble pointing the gun at you w/ you grabbing at him, but you can slash and stab quite easily no matter what he does to grab/push you.
Katana needs more space to use, which limits it up close if the gun still has bullets or you were relying on tight areas to close the distance and now they're restricting your swing.