I don't see any real advantage in this. 2 seconds were shaved off firing 30 rounds with 5 dead rounds so, re-charging to eject the dead ones. With a full mag of live rounds the firing rate isn't going to change.

You need the specific handguard plus the extra parts. The rear charging handle is also there on the rifle so it's just added cost to the rifle to have the forward one as well. There simply isn't enough advantage to justify that extra cost.