Just as the design moves on to the new 'Garand' style gas piston design. Why would anybody want to keep building the old style carbines?
They are already fielding the latest SCAR -- Video here.
I found these facts from a soldier satisfaction survey of the M4:
- 55% requested the firearm be made lighter
- 20% requested a slightly larger magazine
That's not going to happen if they want to keep the same power cartridge. That 30 rounds of 5.56 will always weigh a whole pound. If you want low weight with lots of ammo you're going to have to get something like an FN P-90.