After doing some research, I have found that DPMS has made their uppers in three different heights. The 308B model has the highest of the uppers, and I'm having a really hard time finding a forearm that will make the top rail monolithic. Handguards such as the Troy Battle comes in LP and HP, but even the HP isn't near high enough to mate to my receiver. Has anyone else had any lucking finding a compatible rail for this particular upper? The pic below is what mine looks like.