I was watching a video from Punished Props where he made himself a Borderlands Pistol out of foam. I really liked the look of the pistol. And in the words of Bobby Duke "I want that", so I decided I wanted to make one. But my strong suit isn't foam its 3D printing.
I powered up Fusion 360 and started modeling.

Thankfully he provided blueprints to this prop and many other
https://punishedprops.com/free-blueprint-files/

With those I was able to model the gun shown above.

Assembly Video

For the wall brackets I used the picture hanging strips that you can peel away

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Print instructions

After printing I glued it together using some 3D Gloop
masked of the front of the gun and painted some yellow lines, unfortunately due to capillary actions of the layer lines the yellow bleed through, but I think it gives it character and works for the origins of the prop.