In 1994, armed units of special purpose and the U.S. Marine Corps adopted Colt M4 Carbine is a lightweight and smaller version of the M16A2 rifle. The main differences of the rifle - an easier and shorter barrel and collapsible telescoping stock. The buttstock has 4 positions, as do all the folding stock for AR15/M16 type rifles problematic due to the fact that part of the butt takes recoil damper bolt. All other parts are interchangeable with Colt M16 M16A2.Primenyayutsya stores a capacity of 20 or 30 rounds. When menhih size and weight M4 retains virtually all military specifications for M16A2 firing range up to 400-500m. In 1996, based on the M16A3 rifle was designed similar to shotgun M4A1, distinguished by the presence of type Picatinny rail instead of the integrated carrying handle, as well as a return to full automatic fire, instead of the fire with a cutoff of 3 shots. Picatinny rail allows the installation of a variety of sighting devices (optical, Collimator, night), including standard carrying handles. Based on the M4A1 Colt company developed a number of modifications for both the military and police units.
The most "popular" modifications include: Colt M4 Commando ("Colt M16A2" Commando ", model 733) - the shortest member of the family (total length 76 cm). Its main difference is the decrease in barrel length to 290 mm in all other design model corresponds to the model 723.
Used for firing bullets 5.56 x45 mm.
The experience of counter-terrorism campaign in Afghanistan in 2002 brought not the best reviews of the M4A1. First, a short barrel led to a decrease bullet velocity and, consequently, to reduce the effective range of fire. Second, the barrel and forend rifle very quickly overheat when shooting. Third, the shortening of the trunk and the transfer of vents in the area of higher (compared to the M16A2) pressures led to an increase rate of fire, increasing wear and reducing overall system reliability. Apparently, if the role of self-defense weapons for the crews of combat vehicles M4 still Bole or less adequate, then troops Special Operations, he is still damp.