M4

M4, m4, M04, or M-4 may refer to:

In biology and medicine

In electronics and computing

Firearms and military equipment

Guns and cannons

Military vehicles

BMW M4

The BMW M4 is a high-performance version of the 4 Series automobile developed by BMW's in-house motorsport division, the BMW M GmbH, the M4 is one of the fastest M cars ever produced by BMW achieving 0 to 100 km/h (62 mph) in just 4.1 seconds (equipped with 7-speed DCT automatic gearbox). Part of the renumbering that BMW splits the 3 Series coupe and convertible models to the 4 Series (to further differentiate with the 3 Series sedans), the M4 replaces the M3 Coupe and Convertible models, as well as the Gran Coupe. Upgrades over the standard 4-Series include: a very powerful and responsive, twin turbocharged engine; improved handling, suspension, and braking systems; aerodynamic body enhancements; interior/exterior accents with the tri-colour "M" (Motorsport) badging; the significantly reduced weight compared to the standard 4 series and its predecessor with an all-new stiffer chassis and extensive use of carbon fiber, especially the roof of the car.

F82 M4

M4 carbine

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 (370 mm) barrel and a telescoping stock.

The M4 carbine is heavily used by the United States Armed Forces and is replacing the M16 rifle in most United States Army and United States Marine Corps combat units as the primary infantry weapon.

The M4 is also capable of mounting the M203 grenade launcher. The distinctive step in their barrel is for mounting the M203 with the standard hardware. The M4 is capable of firing in semi-automatic and three-round burst (like the M16A2 and M16A4), while the M4A1 is capable of firing in semi-auto and full automatic (like the M16A1 and M16A3).

History

Following the adoption of the M16 rifle, carbine variants were also adopted for close quarters operations. The CAR-15 family of weapons served through the Vietnam War. However, these carbines had design issues, as "the barrel length was halved" to 10 inches which "upset the ballistics", reducing its range and accuracy and "led to considerable muzzle flash and blast, so that a large flash suppressor had to be fitted". "Nevertheless, as a short-range weapon it is quite adequate and thus, (despite) its caliber, (the XM177 "Commando") is classed as a submachine gun." In 1988, Colt began work on a new carbine design called the XM4 combining the best features of the Colt Commando and M16A2 rifles.