Posting a couple of my Pimp My Gun builds since they take a good few hours to do.
The Devenge STK is an impractically large, extremely heavy, oversized, automatic rifle. This was done as a for-fun gun, so please no comments about how unrealistic the whole thing is. Functionally, the gun would work if it was real, but it would be far too big for real combat usage besides with future mech warriors and such.
Standard: https://www.flickr.com/photos/doomwrathkwld/14530571925
Compact: https://www.flickr.com/photos/doomwrathkwld/24189743010
(Flickr Links because the images are too large to upload directly to the forums.)