HK 40mm Grenade Launcher – SHOT Show 2013
The HK Grenade Machine Gun (GMG) is based on the Mk19 grenade launcher but is highly evolved. The targeting system on this weapon system makes it pretty amazing giving it the capability to do some serious damage to the enemy. Of course this is a military only weapon.
Source: HK 40mm Grenade Launcher – SHOT Show 2013 (Youtube).