Hey Drew, as you study more on your build, you will se the old "cheese grater" quad rail is being replaced with the slim, rounded or "triangle" shaped hand guard's as bjones suggests above. They all come with rail sections so you can still hang all the crap on it if needed.
Checkem out. Even Daniel Defense is offering a slim style. they kinda mastered the quad rail
"I ain't here for a long time, I'm here for a good time"
King George Strait