Cool Guns are great ... until you run out of ammo. Thankfully, you won't be lugging around dead weight when you attach a sharp blade on it, allowing the empty gun to improvise as a Blade on a Stick. Even better when you can detach it and use it as is.
This is a common form of Mix-and-Match Weapon. Many fictional examples have a blade (or blades) permanently attached or even molded to a gun, which [...] [tvtropes.org]