M4 Carbine Assault Rifle

Efran Syah       Firearms    Comment   

The M4 Carbine is a 5.56×45mm NATO, air-cooled, gas-operated, direct impingement, magazine-fed carbine. It has a 14.5 in (370 mm) barrel and a telescoping stock. It is essentially a lighter and shorter variant of the M16A2 assault rifle.

M4 rifle with scope and stock tripod

The M4 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 and service rifle.

M4 Carbine with M203 Grenade Launcher

Equipped with a shorter barrel, collapsible stock and detachable carrying handle (with a built-in accessory rail) it provides soldiers operating in close quarters with improved handling and the capability to rapidly and accurately engage targets at extended range, day or night.

The M203 and M320 grenade launchers can be mounted on the lower hand guard of the carbine. The distinctive step in its barrel is for mounting the M203 with the standard hardware.

The M4-series Carbine achieves over 80% commonality with the M16A2 Rifle and replaces all M3 .45 caliber submachine guns, and selected M9 pistols and M16 rifles.

As with many carbines, the M4 is handy and more convenient to carry than a full-length rifle. The price is slightly inferior ballistic performance compared to the full-size M16, with its 5.5" (14 cm) longer barrel. This becomes most apparent at ranges of 200 yards (180 m) and beyond.

The M26 12-Gauge Modular Accessory Shotgun System (MASS) provides a door breacher, shotgun, and less-than-lethal engagement system as a rifle accessory or as a standalone system without the need for a second weapon

Some features of the M4 and M4A1 compared to a full-length M16-series rifle include:

• Compact size
• Shortened barrel 14.5 in (370 mm), which includes the shorter carbine gas system.
• Telescoping buttstock.

However, 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.

Like all the variants of the M16, the M4 and the M4A1 can be fitted with many accessories, such as night vision devices, flash 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, AN/PEQ-15 multi-mode laser, AN/PEQ-16 Advanced Combat Optical Gunsight (ACOG), and M68 CCO. EOTech holographic weapon sights are part of the SOPMOD II package. Visible and IR (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 (BFA) for training purposes.

The M4 has semi-automatic and three-round burst firing modes (like the M16A2 and M16A4), while the M4A1 has semi-automatic and fully automatic firing modes (like the M16A1 and M16A3).

M4 feedramps are extended from the barrel extension into the upper receiver. This can help alleviate feeding problems that may occur as a result of the increased pressure of the shortened gas system of the M4. This problem is primarily seen in full-auto applications.

The M320, a 40mm grenade launcher, is the replacement to all M203 series of grenade launchers on M16 Rifles and M4 Carbines. An interoperable system, it attaches under the barrel of the rifle or carbine and can convert to a stand-alone

The M4 carbine has been used for close quarters operations where the M16 would be too long and bulky to use effectively. It has been a compact, light, customizable, and accurate weapon. This has come at the cost of reliability and maintainability. Failure to maintain the M4 causes malfunctions. This became apparent as it saw continued use in the sandy environments of Iraq and Afghanistan. Despite this, in post-combat surveys, 94 percent of soldiers rated the M4 as an effective weapons system.

M4 firing with casing in air

Specifications

• Mass:
• 6.63 lb (3.01 kg) empty
• 7.75 lb (3.52 kg) with 30 rounds
• Length:
• 33 in (838 mm) (stock extended)
• 29.75 in (756 mm) (stock retracted)
• Barrel length: 14.5 in (368 mm)
• Cartridge: 5.56×45mm NATO
• Caliber: 5.56 mm (.223 in)
• Action: Gas-operated, rotating bolt, Stoner expanding gas
• Rate of fire: 700–950 round/min cyclic
• Muzzle velocity: 2,970 ft/s (910 m/s) (M855A1 round)
• Effective firing range: 500 m (550 yd)
• Feed system: 30-round box magazine or other STANAG magazines. Magazines with different capacities also available.
• Sights: Iron sights or various optics