page_title: FX-05 Xiuhcoatl
section_title: Design details
hierarchical_section_title: FX-05 Xiuhcoatl / Design details
context_page_description: The FX-05 Xiuhcoatl is a Mexican assault rifle, designed and built by the Dirección General de Industria Militar del Ejército through the Fabricas Militares. The rifle was officially presented in the military parade on September 16, 2006, in the hands of the Special Forces Airmobile Group, GAFE.
  The design was coordinated by the Centro de Investigación Aplicada y Desarrollo Tecnológico de la Industria Militar or CIADTIM and SEDENA and all of its parts are built in Mexico. According to the director of the DGIM, Otilio Ramírez Serrano, by July 2019 approximately 155,000 rifles have been produced. The FX-05 is distributed among the Mexican Armed Forces, and the military industry is aiming to produce 30,000 per year.
context_section_description: Most details about the FX-05 are classified as Top Secret, as this is supposed to be a distinctive indigenously-produced weapon for use by Mexico's elite forces. This is to prevent anti-government and criminal organizations from mocking-up copies to aid in infiltrating secure areas, impersonating military personnel, or appearing to have legitimate support for their cause and its actions. It also helps to prevent hostile or enemy forces from learning the abilities, strengths, weaknesses, and limitations of the new weapon series.
  The design of the weapon is compatible with telescopic, red-dot and mechanical sights and has a folding, adjustable butt stock. The barrel is hammer forged, and the weapon is capable of semi-automatic, three round burst and full auto fire. It has a cyclic rate of fire of 750 rounds per minute. Most of the rifle's receiver is constructed of a polymer reinforced with carbon-fiber with an underlying titanium frame and comes in black, dark-green and desert-tan colors as well as the SEDENA digital camouflage patterns used by the Mexican army. The charging handle can be installed on either side of the rifle with gas piston located above the barrel, which operates under a multi-lugged rotary bolt system. Safety/fire mode selectors are located above the pistol grip on both sides of the FX-05. It can accept NATO-standard as well as specific transparent magazines. In 2017, it was announced that a Mexican-made gripod was in development.
  The internal mechanism and barrel are made of advanced corrosion-resistant stainless steel. An indigenous programmable air-burst grenade launcher is currently under development for the FX-05, which will be able to fire standard NATO munitions in addition to Mexico's new RSE-7 fuel-air grenade round. The FX-05 is also compatible with the AG36 grenade launcher as used on the G36, which is in use until the proprietary design is finalized. In 2017, a Mexican-made UBGL was also demonstrated.
  The FX-05 is one of the world's few assault rifles featuring polygonal rifling, which eliminates the normal grooves of a weapons barrel replacing them with a system of "hills and valleys" in a rounded polygonal pattern. The optical sight is an integrated one with a carry handle attached as standard.
  There has been some criticism that the barrel has reliability issues and a short operating life, blamed on  low-quality materials.
  The FX-05 is available in several configurations optimized for differing use, including: assault rifle (Fusil de asalto), carbine (Carabina), compact (Carabina corta, literally "short carbine"), light machine gun (Ametralladora) and sharpshooter (Francotirador) variants. The variants are all essentially identical, excepting the short carbine having a shortened fore-end and the sharpshooter being equipped with a fixed adjustable stock rather than the standard folding stock.
caption: Normal grooved rifling as used on many rifles (left), compared to the polygonal rifling used in the FX-05 (right)