FX-05 Xiuhcoatl - Legal Status

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 law suit 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.