This guide will tell you how to Unlock Green Camo Neon Loud in Modern Warfare 2.
You will need to boot up your game, then go to your M4 weapon platform and select the FTAC Recon. Now you can unlock the FSS Hurricane. You have to equip this and then click on Gunsmith.
In the gunsmith, you have to go to customize and then you have to click on the camo category and then you have to select Neon loud. To unlock this, you need to upgrade the FSS Hurricane to level 14. You have to get 30 kills well in prone with this weapon to get the solid blue camo.