Will a rail like an FSP cut-out work to extend past the gas block? I imagine a large gap, but I would really like something extending beyond 7". Thanks.
I have a Daniel Defense 9" fsb rail on mine. I fits nicely. I have the pinned factory gas block. I really like the upper. I have approx. 1400 rounds through it with one failure to lock back on the last round. I have cleaned it once and have zero corrosion.