The Colt Advanced Piston Carbine or Colt APC (internal product number P0923) is a lightweight modular 5.56mm caliber piston-operated, magazine fed carbine with a one-piece upper receiver which is capable of firing in

automatic Automatic may refer to: Music Bands * Automatic (Australian band), Australian rock band * Automatic (American band), American rock band * The Automatic, a Welsh alternative rock band Albums * ''Automatic'' (Jack Bruce album), a 1983 el ...

and semi-automatic modes. The design incorporates an articulating link piston that reduces the stresses in the piston stroke by allowing for deflection and

thermal expansion Thermal expansion is the tendency of matter to increase in length, area, or volume, changing its size and density, in response to an increase in temperature (usually excluding phase transitions). Substances usually contract with decreasing temp ...

. Colt submitted the APC as the “Enhanced M4” for the U.S. Army's

Individual Carbine The Individual Carbine was a competition to select the planned successor to the M4 carbine in the United States Army. The U.S. Army conducted an open competition for a carbine to replace the M4. This competition was for the Army only—the Uni ...

competition to replace the

M4 carbine The M4 carbine (officially Carbine, Caliber 5.56 mm, M4) is a 5.56×45mm NATO assault rifle developed in the United States during the 1980s. It is a shortened version of the M16A2 assault rifle. The M4 is extensively used by the US mi ...

in 2012. However, the competition was canceled in 2013 before a winning weapon was chosen. The APC was adopted in limited quantities by several military and law enforcement agencies.

Design

The weapon has a suppression-ready fluted barrel, which is lighter and cools better than previous M4 barrels. It is claimed to have "markedly better" accuracy. To improve reliability, Colt used an articulating link piston (ALP) which "reduces the inherent stress in the piston stroke by allowing for deflection and thermal expansion". In traditional gas piston operating systems, the force of the piston striking the bolt carrier can push the bolt carrier downwards and into the wall of the buffer tube, leading to accelerated wear and even chipped metal. This is known as carrier tilt. The ALP (articulating link piston) allows the operating rod to wiggle to correct for the downward pressure on the bolt and transfers the force straight backwards in line with the bore and buffer assembly, eliminating the carrier tilt. This relieves stress on parts and helps to increase accuracy.

Users

*: Malaysian Special Operations Force units, the UTK and the VAT69 *:

Singapore Police Force The Singapore Police Force (SPF) is the national and principal Police, law enforcement agency responsible for the prevention of crime and law enforcement in the Republic of Singapore. It is the country's lead agency against organised crime; hum ...

, Used by the Special Task Squadron and Emergency Response Team of the

Police Coast Guard The Police Coast Guard (PCG) is a division of the Singapore Police Force that combines the functions of marine police and coast guard in Singapore. Its duties include the law enforcement and search and rescue operations in collaboration with the ...

References

External links

Colt's Manufacturing Company Official
5.56 mm assault rifles Assault rifles of the United States Carbines Colt rifles ArmaLite AR-10 derivatives {{Rifle-stub