Need help taking off M4 outer Barrel
 

So i have removed everything from the outer barrel, the sights, etc. But just as i tried to unscrew the barrel i came across this. What seems to be a small nub stopping the barrel from being able to be unscrewed from the upper receiver. Can someone please tell me how to get rid of this so i can take off the outer barrel? Thanks

Here's a photo. Full size the pic so you can have a better look.

[IMG]http://i1232.photobucket.com/albums/...V/IMG_4455.jpg[/IMG]

You've taken everything that needs to be off. Now the barrel should be able to be pulled straight out. If it's tight, pull harder or spay a bit of silly oil in between the barrel and receiver.

perfect, thanks

That pic isn't very clear, but if you're having trouble pulling the outer out it may be a grab screw.

I think he got it with the first suggestion :P