The HK91 is the semi-automatic-only version of the infamous H&K G3A3 automatic battle rifle manufactured by Heckler & Koch GmbH. The HK91 is the renamed and slightly updated HK41 that fires the 7.62x51mm NATO round and was imported into the United States from 1974-1989. The HK91, like the HK41, was also marketed to civilians however, in order to comply with US firearm regulations, slight modifications had to be made to the HK91 to prevent full-auto customizations. Today, the HK91 model is a highly sought-after collector item due to the limited amount of imported rifles that made it to the US. The G3A3 went on to be the standard issue shoulder-fired weapon for the German Army and was used by various other military forces including Greece, Iran, Mexico, Norway, Pakistan, Portugal, Sweden, Turkey.