Hey guys, not sure if this is posted to the right forum, if incorrect I apologize. I am rather new to Airsoft in general and I want to start doing some modifications to my G&P M4. What I'd like to do is convert it over to an M18 mod 1 with the DD Rail system etc. From what I have gathered in my research though I need a special barrel nut for the G&P as it's a little off. Problem is I can't find this thing ANYWHERE! I've been looking for a solid week to no luck. It seems to be out of stock everywhere I can find. Here is the part I am looking for to give you a better idea: http://shop.ehobbyasia.com/madbull-dd-rail-barrel-nut-for-gandp-metal-m4-reciever.html If anyone can help me track one down I'd be incredibly greatful. Just figured you guys with more experience might have a better idea of good vendors to check.