use. The Fero elevation knob features Bullet Drop Compensation (BDC) settings for in increments calibrated for 5.56×45mm NATO ball ammunition. Accessories Many accessories are based on NATO standard or previously issued items. The rifle can be fitted with a barrel-mounted bipod based on the one issued with the M16A1's cleaning kit. It also uses the bayonet from the G3. It also can mount the FERO Z24-G 4×24 optical sight on a proprietary detachable bracket on the receiver and a clip-on winter trigger. The G41 can also mount a detachable 40 mm HK79 grenade launcher that replaces the synthetic forearm. The weapon in this configuration is known as the G41TGS, or "Tactical Group Support". Variants Note: the 1:178mm (1:7 in) rifling was compatible with the European-standard SS109 round and the 1:305 mm (1:12 in) rifling was compatible with the US-standard M193 Ball round. G41: This is the standard model with a fixed stock and 1:178 mm (1:7 in) rifling. G41A1: This model has a fixed stock and 1:305 mm (1:12 in) rifling. G41A2: This model has a telescoping shoulder stock and 1:178 mm (1:7 in) rifling. G41A3: This model features a telescopic stock and a 1:305 mm (1:12 in) rifling pitch. G41K: This is a carbine (K—Karabiner) variant of the G41A2 with a shortened barrel (reduced in length to the base of the foresight), 1:178 mm (1:7 in) rifling twist rate and a telescopic stock. The G41K is too short to accept the HK79 or fire rifle grenades. G41TGS: The "Tactical Group Support" model adds a HK79 grenade launcher. LF G41: Luigi Franchi made a sample run of the G41, G41A2 and G41K in 1988 for possible production under license; these were later modified for trials by the Italian Army. It differed from the Heckler & Koch model in that it had a polygonal 4-groove barrel with a chromed bore. When the G41 was rejected by the German Bundeswehr in 1989, it was dropped from consideration and the improved Beretta AR70/90 was chosen instead in 1990. The LF G41 however entered use with the Italian commando frogmen (COMSUBIN). LF Mod. 641: A modified variant of the G41 also intended to replace the BM59. It lost out to the AR70/90. Users : Small quantities in service with the Spanish Special Intervention Unit (Unidad Especial de Intervención - UEI) and the Spanish National Police force's GEO counter-terrorist unit who employ the G41TGS. :