The Malfeasance hand cannon from Destiny 2.
*EDIT* For some reason the Hammer doesn't come with the zip files when you hit "Download", however it is in the Object Parts section, just go and get it from there.
The gun in this form is too big, over 3 bananas long!! I'm currently printing it again and 85% scale seems to be about right, scale to your personal needs.
A tricky print. Some parts are duplicated as I have split some down further than necessary. Print whichever ones you feel comfortable with, depending on how dialed in your printer and slicer settings. Supports are needed.
Originally ripped from DestinySTLgenerator which doesn't give much detail and can be a little blocky, but thankfully this gun doesn't have much surface detail to it.
Any questions just ask.