The decision on whether or not the Marine Corps will swap the M16 for the M4 carbine now sits on the commandant’s desk after being endorsed by several major commands, and a final decision can come in weeks. With its shorter barrel, the M4 has a slightly reduced range compared to the M16, but proponents of the carbine argue that its many advantages make up for that drawback.
"Some argue beyond that the M4 carbine lacks effectiveness versus the M16, but the M16 is like driving a sports car with a six-cylinder engine," firearms expert Larry Vickers told Marine Corps Times, due to the fact that both weapons are limited by the same small 5.56mm cartridge. "You can shoot 400 to 500 yards away, but you are still shooting a 5.56."
Though the M16 is, and has been, an iconic weapon of Marine Corps infantry since the Vietnam War, there are many who feel its time has passed, and that the little black rifle, is the future.