Euro is right, but it seems the masses have accepted that FSBs and regular plastic handguards are outdated and you have to run a 13"+ FF rail just to have a flashlight.
A lot of that is probably because most of the big manufacturers only make FF stuff - DD, BCM, etc. - so it's seen as the norm.
For the majority, a 6920 with an Aimpoint PRO and a Surefire Scout on an IWC Mount n' Slot covers all the bases.
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