Water-Cooled .50s: The US Navy Mk22 Pedestal Mount

In 1942, the US Navy adopted the Mk22 Pedestal mount, which fitted a pair of water-cooled Browning M2 machine guns (one left-hand feed and one right-hand). It was used for antiaircraft use primarily, and was also adopted by the Army as the M46 in 1943. The mount was an update to the previous single-gun MK21.

The gunner was protected by a 3/8” (9.5mm) hardened steel shield, and the mount could rotate a full 360 degrees, with elevation from -10 degrees to 80 degrees. They were produced by the Heintz Manufacturing company (no relation to the Heinz company that makes ketchup) of Pittsburgh from 1942 until 1945.


  1. “… no batteries required …” Just add ammo and targets!

    “… to fit my own physiology.” Great word, but I think “physique” would be more precise.

    Thanks for showing this to us, and showing it so clearly and wittily.

      • And the drones have to be able to attack Ian with flour bags or something else non-lethal. The drones also have to be capable of flying in formation and taking evasive action for their attack runs, so that lots more ammo need be expended to down the drones. How many swarms of drones will be reduced to Swiss Cheese before Ian gets covered in flour? JUST KIDDING!!

  2. I have trouble finding information on which USN ships this specific mount was used on. The PT boats had air cooled mounts for their smaller size and lesser weight, but the big ships typically switched away from .50 cal MGs and replaced them with 20mm Oerlikon cannons, because the anti-aircraft range of the .50s was insufficient.

    The manufacturing dates still suggest that this mount was used even after 1942, but I can’t find any ships they would have been on. I am no naval expert by any means, but it would still be nice to know how the mount was used. Interestingly, while their information is not exhaustive, the navweaps.com website does not mention this mount at all and was therefore of no help: http://www.navweaps.com/Weapons/WNUS_50cal-M2_MG.php

    • If the fleet warships were upgrading to 20mm, I’d guess these were “flowing downstream” to the smaller escorts and Liberty Ships.

  3. I thought the 20mm Oerlikon would have replaced the 50 cal in service early on in WWII, but perhaps not. That said, I am looking forward to the video of the guns being fired… there’s going to be one, isn’t there?

  4. I might be mistaken, but I thought these were used mostly in the Pacific theater to protect airfields.

    • That would certainly explain why I can’t find any ships that had them. Even the sub chasers seem to have had 20mm Oerlikons.

  5. This is absolutely begging to be mounted in the back of a Toyota HiLux!!! Having fired the single air cooled M2 off a truck ring mount in combat, I would love to try out a double water cooled setup, I think it would be devastating to the target.

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