need help with identifying rail system size
 

hi i was wondering which one of these are the 7" DD omega rail
because i still want to keep my front sight and not have to use a mk18 style gas block.

http://stickman.rainierarms.com/gall...28%20Stick.jpg
or
http://www.boomarms.com/product_img/BACUST-M4VTS.jpg

those both look like the exact same rail, the difference is the barrel.

awesome, that means i can keep my front sight, thanks :)