China Lake 40mm Pump Action Grenade Launcher

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!


  1. Mark II – Steel locking thingie replaces aluminum one

    Mark III – Synthetic furniture replaces wood (imagine the way VN heat and humidity warped wood)

  2. This indeed is a cool design with greatly augmented fire-power. It is straight forward and logical in the format it is in.

    As I recall, it had a continuation in form of more powerful version while the shot they used was “reduced power” version of 40x53mm high velocity shot. It proved to be a ‘bear’ and development was stopped. Even firing the low velocity grenade is a considerable burden for bearer/ shooter.

  3. The use of the M203 (which denotes the whole rifle + launcher weapon) allows the grenadier to also have a rifle, but can result in carrying LOTS of ammo, and often results in M203 equipped troops limiting the load of one of the two types of ammo. Issuing a pistol to a grenadier using the pump action launcher might offer a better choice when fighting in close (urban/jungle) environments.

  4. I’ve seen the one in the museum in Ho Chi Minh City (formerly Saigon, though many natives still call it that). That was around 2006 and I remember thinking “do video game companies know abou this?!”

  5. Okay, fellers. When I proposed a 4-barrel 40 mm pepperbox design in a comment on Ian’s recent M79 vid, I was lectured on the weight and, especially, the +complexity+ of my idea. (I suggested SA/DA lockwork, but DA-only would probably be better, allowing a 100% enclosed action, no need for a safety, and less of that damn +complexity.+) Full reloads would be quicker than the tube mag we see here. Overall length would be less, esp. w/ a folding stock.* Speed would be greater: 4 trigger pulls.

    I was also chid about loading the grenadier down with too much ammo. SEALS and Marines don’t get chid, of course.

    Not that this pump gun 40 mm is not a cool design. If somebody put a foot or hand outside the box and designed it for a box mag, it might actually persuade me to shut up about my pepperbox.

    * OW! My cheekbone! Okay, file that idea for another time.

  6. Friends,

    After use:
    My cheekbone is bruised.
    My vision is blurred.

    To the doctor:
    Detached retina!
    Nothing hit my eye.
    How did that happen?


  7. I’m not sure how true this is.
    But I met a mention that the device was not developed as a grenade launcher but as an RIOT control tool.
    But the seals (who were allowed to try everything new) liked him as a grenade launcher.

  8. I think I remember hearing that Airtronic tried shopping the idea of a 37mm version around to law enforcement, though I don’t think they ever actually made any.
    Maybe that’s what you’re thinking of?

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