I'm sorry, but everyone who is fighting Stephen is just dumb, no matter how you look at it these models were created incorrectly, and congratulating a guy on his mistakes is just stupid. No one learns from this, and he will just continue to use horrible modeling practices until he gets tired of having sub-par models. You are hurting him more than Stephan has for by killing something important in learning, drive. Tracing a model is simply wrong, taking an image from google and UV Mapping from View is just wrong; this is not someone who is a beginner, it is someone who picked up blender, found out hot to extrude things, and made a cardboard model. Allowing someone to continue this way does not help anyone, but the person it will hurt most in the end is the person who is trying to model, because although he puts hours into it, because of you guys, he never improves.
/rant
Now OP, you need to learn the basics of modeling before you just jump into things.
1) If you ever watched a tutorial that suggested tracing around the model, find that video, unsubscribe from the person, and put him on your ignore list; he is not worth your time. This method is completely incorrect and will get you nowhere.
2) When making a cylinder use <10 sides, otherwise you are just wasting polygons.
3) UV Map from seams
4) Break your model into multiple parts saving polygons
5) Do not take renders of weapons from other games, it is disrespectful to the original developers, causes huge memory loss, and wastes valuable texture space.
Below is a video from a guy making a fairly low poly assault rifle, although I don't like everything he has to say, and his model is a little to high for GunZ, it is a better starting place than where ever you are right now. I don't have the time to work from the ground up, so this is the best I can do for now.
http://www.youtube.com/watch?v=dvDxiGmsmMM