Split front chest rigs are great low profile rigs for those that anticipate a lot of prone shooting. They can be opened up and laid out flat without removing. One of the next purchases from O.S.O.E. will a MD split front rig in the 308 rendition, coupled with my Rallyman Subload I will have 8 spare mags in tap and easily accessible while laying flat on my chest. They are also very easy to conceal under a light shirt if a bunch of crap is not attached to it. O.S.O.E. also makes a 5 mag version for AR/AK that utilizes that “lost” space in the center. See it here:
http://www.youtube.com/watch?v=quMoPMzxYgM