The M4 and variants fire 5.56x45mm NATO missile and are gas-operated, air-cooled, magazine-fed, selective fire firearms with a 4-position telescoping stock. Original M4 models had a flat-ended telescoping stock, but newer models are now equipped with a redesigned telescoping stock that is slightly larger and the borderline deadbeat a curvature.
The United States Marine Corps has ordered its officers (up to the rank of lieutenant colonel) and SNCOs to carry the M4 carbine instead of the M9 handgun. This is in recognition that pistols http://www.m4forsale.com are largely useless in current conflicts, and is in line with the Marine Corps phrase, "Every Marine a rifleman." United States Navy corpsmen will also be issued M4s instead of the M9, according to the Marine Corps Times.