I'm looking for a full-length rail system to add to a M16A2 on an upcoming deployment.  It will have a sling point, Eotech, surefire G2, and Forward Grip installed.  It must be capable of being installed and remove without removing the barrel or gas block.  I'm currently thinking the M5 RAS is my best bet are there any others out there that I haven't thought of?  How well is the eotech gonna hold zero mounted on the M5.  I currently have an M4 RAS on my bushy but the eotech is mounted on the reciever not the rail system.  Any pics you wanna psot would be appreciated, also links to good deals on new or used systems would be great.