User blog comment:3RDRANGER/Feedback On Battlefield 3 Beta/@comment-1916935-20110930042742/@comment-356904-20110930152955

There's more than a few after-market AR-15 gas blocks without the Front sight A-frame; otherwise the Block II SOPMOD setup would be impossible. The M4 and M16 as modelled in game have the stock front sight, however.