Need help with new gun build

https://i.servimg.com/u/f64/15/74/29/33/myweap14.jpg
I wana make a M4 that looks like this
I have a base gun and a folding stock but I need help finding an outer barrel and gas block.
there are so many different barrels out there I dont know what to get
I need help finding a barrel that will give me the look of the gun in the picture


any help at all would be appreciated

i dont see any barrel so i dont think it matters which one you use(besides that it needs to be short and end right at the end of the handgaurd) all i see is http://www.airsoftpost.com/product_info.php?cPath=25_87&products_id=32160 , http://www.airsoftpost.com/product_info.php?products_id=30518 , http://www.airsoftpost.com/product_info.php?products_id=30870 , and http://www.ebairsoft.com/micro-scope-mount-p-1909.html .


very interested in how your OD upper reciever will look.

yeah thats the point i need the gas block to be the end of the barrel and have only the threads stick out