The M4A1 Carbine is a highly versatile compact version of the M16 Assault Rifle and a variant of the ArmaLite AR-15. It is the standard-issue weapon of a number of nation's armed forces and law enforcement agencies, including those of Osea and the ISAF. I has for standardized picatinny rails, and with a large assortment of possible attachments, this allows for great number of possible customizations. It shares the same types of magazines and 5.56x45mm NATO cartridge with the M16, however it is slightly inferior in terms of ballistic performance to its cousin, due to its barrel being almost 15cm shorter. The M4's biggest weakness is it's gas piston firing system, which requires the weapon completely disassembled when jammed, but M4A1 is an overall exceptional weapon.
This article is under construction. Other users are welcome to contribute to it.