I just got my 9" rail off the classifieds, and it came with the rails, the 6 screws, and the mounting ring? (small piece that the screws go into) Am i missing a piece because I can't figure out how to install this thing...
http://i281.photobucket.com/albums/k...5/5a21e0d7.jpg

To install...first remove the stock things...
1. Remove handguards
2. Remove front sight/gas tube
3. Remove delta ring (you might find a rubber o-ring under the deta ring on the outer barrel...leave it on the outer barrel)

Then install the new system.
1. Screw that part you linked as a picture onto the receiver threads...(it replaces your delta ring)...it only goes on one way (the side facing up is the edge closest to the receiver.
- it needs to be positioned right...from your picture...the edge that is just past 3 o'clock is the bottom...the opposite side will have a "nub" that's solid...if it had a hole in it you could pass your fake gas tube through that (I drill mine out to do that).
2. Line up your handguard. Check that it's centered/straight/etc..
3. Tighten up the 6 screws...best to do them all just barely tight...then to snug each of them down like you would for a wheel on a car...(alternating sides in a star pattern).
4. Put on your gas tube/front sight/block whatever

Thanks M102404, I figured out that the barrel nut was just stuck inside the screw ring. It's installed now :D

How many Inches is the RAS?? Because I'm from California and I can't find it on any US websites because they label them in Inches

9.5.

thanx found it on AirsoftGi