Marine Corps Eyes M249 SAW Replacement

It looks like the Marines are looking at partially replacing their belt fed M249 SAW with a lighter magazine fed automatic rifle.

They are hoping for a 12 lb weapon to replace the 17 lb SAW.

Given that they are also dropping the quick change barrel as a way to get there, and using a slower rate of fire to deal with barrel heating this implies a significant drop in firepower.

Not having served, I'd appreciate any comments from people who have about the merits of such a change.

The US army is looking for a lighter weapon too, but they are sticking with the high rate of fire and belt feed.