FX-05 Xiuhcoatl

The FX-05 "Xiuhcoatl" (literally, "turquoise-serpent" in Classical Nahuatl; metaphorically or descriptively, "fire serpent") is a Mexican assault rifle, designed and built by the Dirección General de Industria Militar del Ejército (Directorate General of the Army Military Industry). The rifle was officially presented in the military parade on September 16, 2006, in the hands of the Special Forces Airmobile Group, GAFE. (Grupo Aeromóvil de Fuerzas Especiales). The design was coordinated by the Centro de Investigación Aplicada y Desarrollo Tecnológico de la Industria Militar or CIADTIM (Center of Applied Research and Technology Development Military Industry) and SDN and all of its parts are built in Mexico. It is currently in use by the Mexican Army.

Development
The development of the FX-05 began as a 16-month research back in 2005 with CIADTIM as part of research efforts to replace the HK G3A3 rifles that were in service with the Mexican military. Originally the HK G36 was supposed to become the Mexican military's standard rifle as plans were already drawn to transfer technology and equipment to Mexico to initially build 30,000 rifles at a cost of € 63,016,125 as part of Mexico's military modernization program. The Mexican government ultimately decided that they wanted a more cost effective alternative to the G36, which resulted in the decision to end the project before any technology or equipment could be transferred and the FX-05 project was undertaken. A Mexican report states that up to December 2006, $84,000,000 Mexican Pesos (€ 5,855,698 at the December 2006 exchange rate) were invested in the FX-05 project, including raw materials and using only national equipment and technology. Leading the FX-05 project was General Alfredo Oropeza Garnica with Brigadier General Jose Antonio Landeros.

Design details


The design of the weapon includes telescopic, red-dot and mechanical sights; cold-forged barrel; folding and adjustable butt stock; as well as the capability to 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-fibers 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 barrel system. Safety/fire mode selectors are located above the pistol grip on both sides of the FX-05.

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. But until it is finalized the FX-05 will use the AG36 grenade launcher as used on the G36. 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.

The FX-05 is available in several configurations optimized for differing use, including; Assault rifle, Carbine and Short Carbine. A light machine gun and sharpshooter version is also being made available.

Legal status


On February 1, 2007, representatives of the SEDENA (Secretaría de la Defensa Nacional) and Heckler & Koch met in Mexico City to address accusations of patent infringement from the German firm. They claimed that the Army "replicated" the design of the HK G36 assault rifle. After an exhibition of detailed models of the FX-05, the HK representatives were convinced that, despite the similarities between the two rifles, there wasn't a patent infringement, therefore bringing an end to the disagreement. In the end, the German firm stated that they would not sue on the basis that even though the rifle looks similar it is internally different with a completely different mechanism.

The report concluded that while externally the FX-05 bears obvious design elements there are several notable differences. The receiver which was styled after the G36 is in fact coupled with a simple gas piston similar in operation to the AK series which is then attached through a delayed roller system to the weapons recoil delaying system. While the more advanced parts of the rifle were found to be independently Mexican produced, Heckler & Koch officials still questioned the DGIM (the manufacturer of the FX-05) regarding the issue of the rifles receiver system which is almost identical to the G36's. It is believed that the receiver was made to be as similar to the G36 to maximize commonality between the two weapons as many of Mexico's police forces are issued with the G36. Either way it appears that the newer post lawsuit versions of the FX-05 feature a different newly designed receiver, as the newer FX-05 come with a four position fire selection (safe, single shot, three round burst, full auto) whereas the original FX-05 came with only three firing selections (safe, single shot, full auto). This theory is also reinforced by the fact the new black FX-05 models feature a visible metal protrusion before the magazine ejector and the receiver is noticeably smaller. The influence of the G36 receiver, AK styled gas piston and Mexican recoil delaying system can all be seen in the rifles partial cut away image.

Comparable Weapons

 * FN SCAR
 * Heckler & Koch G36
 * Heckler & Koch XM8
 * Bushmaster ACR