I somewhat agree. The M-4 carbine is just a shortened M-16. If the M-16's are doing okay, why aren't the M-4'sArmy Carbine Program May Waste $1.8 Billion, Report Finds.
I THINK I have an answer. The M-16A3 is not fully automatic but will shoot in three-shot bursts. They are issued to normal soldiers who often lack "ammo discipline" where as more elite soldiers are issued M-4's. I am sure the special forces think three-shot bursts are poocy as they have more "ammo discipline".
How many times have you seen movies about Vietnam and someone gets shot at and ten soldiers jump up and spray bullets ..... until their 20-round mags runs out. And then you have ten soldiers swapping mags and the VC jump up and start shooting.
The real combat soldiers know how to conserve their ammo until they really need it!