The M4 carbine is a shorter and lighter variant of the M16A2 assault rifle.
The M4 is a 5.56×45mm NATO, air-cooled, direct impingement gas-operated, magazine-fed carbine.
It has a 14.5 in barrel and a telescoping stock.
The M4 carbine is extensively used by the United States Armed Forces and is largely
replacing the M16 rifle in United States Army and United States Marine Corps combat units
as the primary infantry weapon.
Facts -The first model called XM4, which was renamed
to M4 in May 1991, had an Upper A1 Sight, and was given a shorter 11.5-barrel, but later
it was given a longer 14.5-inch barrel for the bayonet and the M203 Grenade Launcher.
-There have been some criticisms of the carbine, such as lower muzzle velocities and louder
report due to the shorter barrel, additional stress on parts because of the shorter gas
system, and a tendency to overheat faster than the M16A2.
Design The M4 is handy and more convenient to carry
than a full-length rifle.
While the M4's maneuverability makes it a candidate for non-infantry troops, it also
makes it ideal for close quarters battle.
The M4 have mostly replaced the M16A2 in the Army and Marines.
The U.S. Air Force, for example, has transitioned completely to the M4 for Security Forces squadrons,
while other armed personnel retain the M16A2.
The US Navy uses M4A1s for Special Operations and vehicle crews.
Some features of the M4 compared to a full-length M16-series rifle include:
- Compact size - Shortened barrel 14.5 in, which includes
the shorter carbine gas system.
- Telescoping buttstock
Functionality The M4 is capable of mounting the M203 and
M320 grenade launchers.
The distinctive step in its barrel is for mounting the M203 with the standard hardware.
The M4 is capable of firing in semi-automatic and three-round burst modes, while the M4A1
is capable of firing in semi-auto and fully automatic modes.
Reliability
The reliability of the M4 has increased as the design was upgraded.
In 1990, the M4 was required to fire 600 mean rounds between stoppages using M855 ammunition.
In 2013, the current M4A1 version can fire 1,691 mean rounds between stoppages using
M855A1 ammunition.
Accessories
The M4 can be fitted with many accessories, such as night vision devices, suppressors,
laser pointers, telescopic sights, bipods, either the M203 or M320 grenade launchers,
the M26 MASS shotgun, forward hand grips, and anything else compatible with a MIL-STD-1913
Picatinny rail.
Other common accessories include the AN/PEQ-2 and AN/PEQ-15 multi-mode laser and light modules,
Advanced Combat Optical Gunsight, and M68 CCO.
EOTech holographic weapon sights are part of the SOPMOD II package.
Visible and infrared lights of various manufacturers are also commonly attached using various mounting
methods.
As with all versions of the M16, the M4 accepts a blank-firing attachment for training purposes.
In January 2017, a USMC unit deployed with suppressors mounted to every infantry M4 service
weapon.
Exercises showed that having all weapons suppressed improved squad communication and surprise
during engagements; disadvantages included additional heat and weight, increased maintenance,
and the greater cost of equipping so many troops with the attachment.
Specifications Weight
Empty: 6.5 lb 7.49 lb with 30 rounds
Length 33 in when the stock is extended
29.75 in when the stock is retracted
Action Gas-operated, rotating bolt
Rate of fire: 700–950 round/min cyclic Muzzle velocity: 2,970 ft/s
Effective firing range: 500 m Feed system: 30-round box magazine or other
STANAG magazines.
Magazines with different capacities also available.
Sights: Iron sights or various optics