Garry's Mod Compiling error

Hey guys I’ve been working on a Commander Colt model but for some reason when I put the modeling shit in game the model is just a shadow. I can physgun beam it and Its invisible. I tried painting over it with a paint tool and it shows up. (the outline) Anyone got any ideas?

This is the image: http://images.akamai.steamusercontent.com/ugc/271725310715384007/1CB1919C75D2A7CFE454BBF2CB52099D3978F95C/
Thanks.