Alright, I think we have all established that the Spartan in the middle of the picture is holding an Assalut Rifle, am I right? Well, I'm on Halopedia and I currently am comparing the difference between the AR in Halo C.E. to the AR used in Halo 3 and Halo 3: ODST and I have come to the conclusion that the AR the Spartan is holding is the Halo 3 and ODST Assault Rifle because of it's barrel size. The Halo C.E. AR has a smaller barrel than the barrel of the AR in the picture, and the Halo 3 and ODST Assault Rifle has a longer barrel (around the barrel size of the AR in the picture) which is what made the gun more accurate. This is what I believe so I could be wrong, or it might be a whole new type of AR we haven't seen yet that is similar to the Halo 3 and Halo 3: ODST AR. =/