World's 10 most ferocious weapons in use

4. HK M320 Grenade Launcher

 

M320 Grenade Launcher Module (GLM) is the U.S. military's designation for a new single-shot 40 mm grenade launcher system to replace the M203 for the U.S. Army, while other services will keep using the older M203. The M320 uses the same High-Low Propulsion System as the M203.