Possibly the coolest small arm used by the United States in the Vietnam War was the China Lake 40mm pump action grenade launcher. Only 24 of these were made, each fitted by hand. Of those, 2 went to MACVSOG, 2 to Army Force Recon, and the remaining 20 the the Navy SEALS. They were used as an ambush initiation weapon, with 4 rounds of rapid-fire 40mm HE grenades available.
Only five original examples survive today; four in US museums and military institutions and one in a museum in Saigon. An effort was made in 2004 to build reproductions, it is one of those used in this video. This project was not ultimately successful, but did lead to a very interesting series of events with the Airtronic company and the US Marine Corps, which will be detailed in a following video. Special thanks to Dutch Hillenburg and Kevin Dockery for making this video possible!