Originally Posted by Ricochet
No, you said it clearly; I just missed that part of your post. Apologies.
No problem. It looks as if we all came to the conclusion, that they currently don't exist. If they did it would be illegal, due to it being classified as a replica. While searching around the web, I remember a molding/casting method I used for making the outer shell of a Spitfire in my last year of high school.
I'm pretty sure I can use the same method to achieve what I'm trying to get, this can go two ways though. The more tedious way involves making a foam model first, then using that to create silicon molds to pour plastic resin into. The second option is as most members stated above; to buy a broken AEG or GBB M4 (minus the hand guards, pistol grip, stock and rear/front sights) and use that to make molds.
Just want to thank everyone for their feedback and suggestions, I really appreciate it.