It is impossible to find this rail unless it goes by another name. I didn't want to remove the barrel nut to switch the rail since I do not have the tools to re-torque it back and to be honest, I actually like the look and feel of the rail despite the weight. I just purchased the 8.5" PSA upper but it comes with a 7" rail instead of an 8 or 9". It would be a little better aesthetically (to me at least) with the replaced muzzle brake to have a bit of a longer rail system.
I found that a couple other complete uppers come with the SQR 9" rail but I have been only able to find the 11" and 13.5" listings (out of stock of course). Does the 9" version exist as an orderable part? Thank you for any response! (The link to my listing and the other listings are below as well)
http://i98.photobucket.com/albums/l272/southkhaki19/PSA%20AR-15%20and%20Gun%20Accessory%20Case/PSA85inAR-15PistolComplete.jpg
My 8.5" Upper w/ SQR 7"
http://palmettostatearmory.com/index.php/psa-8-5-5-56-nato-1-7-melonite-sqr-7-without-bcg-or-charging-handle.html
Others with the SQR 9" version
http://palmettostatearmory.com/index.php/psa-10-5-chf-sqr-9-with-bcg-and-charging-handle.html
http://palmettostatearmory.com/index.php/psa-12-chf-5-56-sqr-9-upper-without-bcg-or-charging-handle.html