Quoted:
The Navy SEAL collection at the SEAL UDT Museum had a Hush Puppy suppressor on a commercial S&W pistol and not a NavSpec Hush Puppy.  There are a few reasons why there are no real Navy issue Hush Puppy pistols in museums outside of the Navy and DoD, but it really is classified.

The Navy Museum, NavSEA Museum at Crane, IN and Aberdeen have complete S&W Hush Puppies, as in pistols, suppressors, rebuild kits for the suppressors and spare ammo packs with waterproof kits.  The Ct Valley Historical Society Museum has the S&W collection, and in it is Roy Jink's non-US marked Hush Puppy with fake suppressor, which was actually built by S&W employee Tom Campbell, from parts left over in the S&W R&D Section of the factory, along with 2 models that S&W assembled of the single stack and double stack versions.  A friend of mine from Texas had the pistol with the complete backstrap set for the S&W detachable stock in his S&W military collection, but he passed on several years ago and S&W or Jinks bought it back at auction for about $1500.

Reed Knight has the 1970's and 80's vintage upgrade of the Hush Puppy system for the Navy in his collection, which was built on the Beretta 92SB and 92SBF models.  I know he was given a original S&W stock for the Hush Puppy, but I do not think he ever got a Smith pistol in his extensive personal S&W collection.

The system was used by the military until very recently, even though it was very obsolete - but it has a low survival rate since the slides crack due to the thin slide cross section where the locking notches are cut.  I have fired a Hush Puppy Mk 22 single stack pistol with a 1980's fixed baffle suppressor in 1984 at Little Creek and it was very quiet.  I was told that the wiped version from Vietnam was just as quiet.  A few years ago I got to fire a vietnam era Hush Puppy with 40 year old ammo and wipes that were starting to go bad.  It was extremely quiet, but the bullets did not make it to the 15 yard line since the wipe pack caused bullet yaw.

A gunners mate and civilian Wage Grade Weapons smith for the Navy proceeded to re-engineer a new wipe pack in the same Hush Puppy suppressor tube - only without the spring inside.  It was basically a 3 baffle unit that screwed into the front cap of the silencer.  The back of the suppressor was lined with a thin film of hydro jelly, which I think was medical gel for sonagrams.   The Hush Puppy swimmer baffle/plug was placed into the cup of the muzzle cap.  All you could hear was the hammer hit the firing pin and the bullet hit the cardboard back stop.  The suppression effect only lasted 3-4 shots before you had to re-gel the unit.

The slide did look like it was taking a beating and the nut that held the slide lock mechanism all together did let go. The original cap nut was loose and was field replaced by the Gunner by a castle nut.  It probably still soldiers on with TZZ blue tip subsonic ammo with a secret intel agency.  I know since a certain intel agency ordered a bunch of FMJ subsonic ammo in 158 grain weight.  That bullet is nice, but the profile was the only thing that fed in the S&W pistols without fail.  The Knight made loads actually caused weapon failures.  There are plenty of better systems out there - H&K and ACC short suppressors are used by the Navy now and they still use the P226 and the long AAC suppressor in NSW.

Navy Collection HP
<a href="http://s1120.photobucket.com/user/LogSu2/media/SampWMk22_zps2e2ca307.jpg.html" target="_blank">http://i1120.photobucket.com/albums/l481/LogSu2/SampWMk22_zps2e2ca307.jpg</a>
<a href="http://s1120.photobucket.com/user/LogSu2/media/SEALNam4.jpg.html" target="_blank">http://i1120.photobucket.com/albums/l481/LogSu2/SEALNam4.jpg</a>

S&W Collection HPs - only 2 outside of Government hands - supposedly, but I know of 2 registered ones in Maryland.
<a href="http://s1120.photobucket.com/user/LogSu2/media/SWHPMK22_zpse4a46771.jpg.html" target="_blank">http://i1120.photobucket.com/albums/l481/LogSu2/SWHPMK22_zpse4a46771.jpg</a>

<a href="http://s1120.photobucket.com/user/LogSu2/media/A147000display_zps0e7a9277.jpg.html" target="_blank">http://i1120.photobucket.com/albums/l481/LogSu2/A147000display_zps0e7a9277.jpg</a>

Hush Puppy reload kit with ammo and pistol waterproof plugs and suppressor muzzle plug.
<a href="http://s1120.photobucket.com/user/LogSu2/media/Dev%20Treasure/DSC_00852.jpg.html" target="_blank">http://i1120.photobucket.com/albums/l481/LogSu2/Dev%20Treasure/DSC_00852.jpg</a>

Most operators seem to prefer using a suppressed shorty M4 or MP7 suppressed instead of relying on a obsolete concept of using a handgun close in.  

Think this project is very nice.   Very retro old skool!

Note: These are not my pictures so use google and give credit to where its due if you repost them.