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The MK 22: AKA ‘The Hush Puppy’

The MK 22: AKA ‘The Hush Puppy’

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Travis Pike

Travis Pike

The MK22, also known as the “Hush Puppy,” holds a unique and intriguing place in the annals of military history. This suppressed pistol played a crucial role in the covert operations of the Navy SEALS during the tumultuous years of the Vietnam War. With its quiet lethality and covert applications, the story of the MK22 offers a captivating glimpse into the the innovation and adaptation of weaponry in one of the most challenging combat environments of the 20th century. In this article, we delve into the fascinating history of the MK22, exploring its development, deployment, and the impact it had on the development of the modern suppressed handgun. 

MK22 Hush Puppy. (Photo: Hampton Roads Naval Museum)
MK22 Hush Puppy. (Photo: Hampton Roads Naval Museum)

Suppressors have been around since 1902 but didn’t see significant combat use until the Second World War. The Spy Masters of World War II saw the advent of numerous suppressed weapons, often specialty weapons like the Welrod Assassin’s Pistol. Years later, the conflict in Vietnam exacerbated the use of suppressors in the modern era and their usefulness in asymmetric warfare.

Special Operations forces in Vietnam saw the value of suppressed weapons, especially when working well behind enemy lines. It was in Vietnam that the foundation of the modern American commando was laid. This era witnessed the rise to fame of elite units such as the Green Berets, Navy SEALs, and Marine Recon, who continue to be celebrated today. The formation of the Joint Combat group, MACV-SOG, marked the amalgamation of numerous special operation forces into one elite group. These men had a special mission and required special weapons. One of their more exciting designs came from the SEALs and was known as the Mk 22 MOD 0, affectionately known as the Hush Puppy.

MK22 with silencer. (Photo: US Navy)
MK22 with silencer. (Photo: US Navy)

The Hush Puppy - Keeping It Quiet

The name “Hush Puppy” offers a bit of a clue as to the weapon’s purpose. The SEAL teams and MACV-SOG were looking for an extremely silent pistol. These teams were using a variety of handguns at the time, including the old Welrod design from WW2 and a suppressed Walther PPK. They wanted something larger, quieter, more powerful, more modern, and easier to aim.

The “Hush Puppy” moniker came from the need to eliminate guard and alert dogs used by enemy forces. They wanted a quiet weapon that could dispatch the guard dogs without raising any alarms. They also wanted to eliminate sentries or wandering enemy troops without alerting potential nearby enemy forces. 

The job of creating this new weapon fell to the Naval Special Warfare Lab. At the time, SEALs were equipped with the S&W Model 39 pistol, which initially featured a single-stack design for 9mm rounds. However, later iterations were adapted to accommodate a wider grip and a 14-round magazine. The mad Naval scientists transformed these handguns into the Mk 22 MOD 0. It bears mentioning single stack Mk 22s were rare, with the double-stack variant being more prevalent.  

A diagram of the MK22 Hush Puppy from "Small Arms of the World."

The Mk 22 MOD 0 - The Modern Silenced Handgun

What makes the Mk 22 MOD 0 so interesting is its pivotal role in shaping the modern suppressed handgun. To achieve this, it departed from the conventional blowback-operated system, like the PPK, and embraced a short recoil-operated mechanism with a locked breech. The S&W Mk 22 is one of the earliest examples of a handgun that utilized a piston or Nielsen Device to allow for reliable cycling when suppressed. 

The transformation also extended to the barrel, which had to be extended and threaded to accommodate the attached suppressor. The creators also installed suppressor height sights, making it much easier to aim than previous suppressed semi-auto pistols. To further aid in aiming, a detachable metal stock was added. This likely helped improve accuracy by leaps and bounds. A third point of contact makes shooting much easier, and when you are trying to silently pick off an enemy threat, you don’t want to fire more than one shot.

Smith & Wesson MK22 Mod 0 Hush Puppy with metal stock
Smith & Wesson MK22 Mod 0 Hush Puppy with detachable metal stock.

Lock It Down and Keep It Quiet

It’s tough to find first-hand accounts of the Mk 22 in the field, but the users seem to have been pleased with its performance. Notably, it remained in service within the SEAL teams well beyond the Vietnam era. We know that several dozen were sent overseas. Finding exact numbers is tough, but according to Kevin Dockery’s book “SEALs In Action,” it’s reported that SEAL Team 2 had a substantial arsenal of 45 Hush Puppies.

Roughly 120 MK22 Hush Puppy pistols were produced overall. Only two ever left the military and made their way to private owners. The Mk 22 MOD 0 is a fascinating pistol, and it really set the stage for modern suppressed handguns. The slide lock feature isn’t super popular but the raised sights, threaded barrels, and pistons are all elements of modern suppressed handguns. It’s a fascinating solution to a somewhat complicated problem, and unlike a lot of Vietnam-era silenced weapon experiments, it worked! 

MK22, suppressor removed. (Photo: US Navy)

The MK22 Hush Puppy: Silent Power in the Field

You might not have been able to fire more than one shot, and this unique pistol introduced a fascinating mission-specific feature. While most semi-auto handguns have a slide lock that keeps the slide open when the gun runs out of ammo, the Mk 22 MOD 0 had a slide lock that kept the slide closed. Although optional, this innovation significantly enhanced the pistol’s suppression capabilities.

Exactly how did it improve the pistol’s suppression capabilities? Well, as you know, guns make a lot of noise when fired, thanks to multiple elements: the explosion at the end of the barrel, the supersonic crack of a round breaking the sound barrier, and one more we often ignore, the often overlooked sound of the action clacking back and forth. The slide lock on the Mk 22 eliminated this aspect of the noise but, in turn, rendered the weapon a single-shot-only design. 

The Navy paired the Hush Puppy with the Mark 3 suppressor. Measuring five inches in length and weighing 8 ounces, the decision was made to employ a wipe-based suppressor. During that era, a sealed wipe-based suppressor delivered an exceptionally quiet option. To the extent that when fired from an unsealed Mark 3, the loudest noise was the slide’s movement, hence the inclusion of a slide lock.

Wipe-based suppressors necessitate periodic wipe replacemen. The Mark 3’s wipes lasted about 25 rounds or so, but suppression got worse and worse as the weapon was fired. Users could swap cores to replace the wipes when needed. Keep in mind suppressor technology has advanced by leaps and bounds since the Vietnam War. Modern suppressors will last nearly forever and are exceptionally durable and quiet. 

Finally, the weapon was also issued with 158-grain 9mm ammo. This special, heavy 9mm was subsonic and moved at only 900 feet per second. 

MK22 Mod 0 Hush Puppy. (Photo: US Navy)
(Photo: US Navy)

An Iconic Piece of Suppressor History

In summary, the MK 22 Hush Puppy remains an iconic piece of suppressed firearm history. Its quiet power, developed during the challenges of the Vietnam War, redefined what a suppressed handgun could achieve. From the unique slide lock mechanism to the formidable Mark 3 suppressor and specialized subsonic ammunition, the Mk 22 was ahead of its time. While it may no longer be in service, the legacy of the Hush Puppy endures as a symbol of innovation and adaptability in special operations weaponry.

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