Journal · Collector’s Guide
KAC Snap-On Suppressor and the Slide-Lock Beretta 92F
Knight’s Armament built the KAC Snap-On suppressor as an upgrade to the Vietnam-era Hush Puppy, and it rides on a Beretta 92F modified with a slide lock and a longer barrel. Lock the slide shut and the pistol does not cycle when it fires, the same trick Navy SEALs used with the Smith & Wesson Hush Puppy. The set in our photos carries one serial number on the pistol and the suppressor. It is part of the Old Steel Arsenal collection, and we’re not shooting it, so what follows is what the photos show plus what published tests report, not our own range results.
The original Hush Puppy
During the Vietnam War, SEAL teams carried either a standard Smith & Wesson Model 39 or a modified version, the 9mm Pistol Mark 22 Mod 0, called the Hush Puppy. It was developed in the 1966–67 time frame, according to Small Arms Review, and the Navy’s request was carefully worded as a means of quietly eliminating guard dogs. That is where the nickname came from. Small Arms Review puts the number made for the Navy at 100 to 120.
The Mark 22 got a longer barrel, higher sights and a special slide latch. When its rear was pressed, triangular tips on both sides engaged cuts in the slide, so the action stayed locked during firing. That made the pistol a manual repeater, fired once and then racked by hand, but it took the sound of the action out of the shot. Its Mark 3 suppressor held soft urethane disks; the first bullet made the hole the others passed through, and the insert was replaced after 24 shots or when the sound rose too far. Small Arms Review gives rough conversions of the original measurements: 160 decibels unsuppressed, 133 suppressed with the slide unlocked, and a 129-decibel peak with the slide latch engaged and the Navy’s Mk 144 subsonic load. Treat those as historical reported figures, not a controlled test of the lock alone.
A Beretta 92F built on the same idea
The pistol here is a Beretta 92F, marked BERETTA U.S.A. CORP. ACKK., MD.-MADE IN USA and MOD. 92F-CAL. 9mm Parabellum-PATENTED. The U.S. military adopted a version of Beretta’s 92 as the M9 service pistol in 1985, replacing the M1911A1; this 92F is a commercial-marked gun, not an M9. It has two additions: a slide-lock arm under the frame and a barrel long enough to stick out past the slide and take a suppressor.
How does a slide lock make a suppressed pistol quieter?
The arm sits on the frame just under the slide. Push it up and its lug catches the slide. Locked, the slide won’t move when the pistol fires: no action noise, no gas out of the ejection port, and the empty case stays inside. For the next shot the slide is racked by hand. RECOIL, shooting a slide-lock 92F of this type, found the lock dropped from the slide on its own after every shot, which made the rack, eject and reload quick, and describes the lock as ambidextrous. That was RECOIL’s test gun; ours has not been fired, so we have not seen how its lock behaves after a shot.
A locked slide also takes self-loading out of the equation: with the pistol worked by hand, the extra weight of a suppressor on the muzzle cannot cause cycling malfunctions. For pistols meant to fire suppressed and still cycle on their own, the later answer was the Nielsen device, popularized by Mickey Finn of Qual-A-Tec, which lets a tilting-barrel pistol run with a suppressor. The 92F does not have a tilting barrel and, as RECOIL notes, does not use such a device. According to RECOIL, slide locks became uncommon after that.
What is the KAC Snap-On suppressor?
According to RECOIL, KAC built the Snap-On as an upgrade to the 1960s Hush Puppy. The first Snap-Ons threaded on; the second generation used a locking gate latch that attached quickly to a barrel machined for it, a taper-pin mechanism RECOIL credits to KAC engineer John Anderson. The same article gives the suppressor’s official issue name as the XM-9 (not to be confused with the XM9 pistol trials) and reports that the U.S. Air Force took 3,800 Snap-Ons for pilot escape-and-evasion kits and Air Force special operations teams. Ours is marked MFG.BY KNIGHT'S ARMAMENT CO. VERO BCH, FL., 9MM SNAP-ON, and SER. NO. with the pistol’s own serial number.
The can is short and fat, about 1.5 inches across and a little under 5.5 inches long by RECOIL’s measurement, and it blocks the pistol’s own sights. So it has its own on top: the top of the rear gate-latch assembly serves as a notch rear sight, and a bead front sight is threaded in near the front of the tube.
How the wipes work
By RECOIL’s description, most of the Snap-On is a large gas expansion chamber. After that the bullet runs through a stack of rubbery polyurethane wipes separated by spacers, seven or eight of them. Some wipes have small holes or cross cuts; others are solid and the first bullet makes the hole. The elastic material closes in behind the bullet and slows the gas escaping after it, which, together with the expansion chamber, makes the shot quieter. But every shot wears the wipes, and the holes grow.
How long they last is the weak point. RECOIL says wipe life depends on the ammunition and rate of fire, with supersonic loads wearing them much faster, and that the whole wipe and spacer set can be swapped in the field. It gives no round count for the Snap-On, and we have not tested ours. On RECOIL’s test gun the bullet had to push through more than three-quarters of an inch of polyurethane, which the reviewer blamed for mediocre accuracy, and hollow points are out.
Why we like it
Our owner’s first air pistol as a kid was a 92. Now he’s got a real one built around a SEAL idea, and honestly, he just thinks it’s cool.
Specifications
| Item | This set (size and internals per RECOIL) |
|---|---|
| Pistol | Beretta 92F, Beretta U.S.A. Corp., Accokeek, Maryland |
| Cartridge | 9x19mm Parabellum |
| Modification | External slide lock, extended barrel |
| Suppressor | Knight’s Armament Co. 9mm Snap-On, Vero Beach, Florida |
| Suppressor size | About 1.5 in diameter, under 5.5 in long (RECOIL) |
| Suppressor sights | Bead front on the tube, notch rear on the latch assembly |
| Internals | Expansion chamber, polyurethane wipes and spacers (per RECOIL; not inspected) |
| Serial | Same number on the pistol and the suppressor |
On the floor at OSA
The Beretta and its suppressor are part of the Old Steel Arsenal collection and are not among the pieces linked below. These are related pistols in our case:
- An Auto-Ordnance 1911 in .45 ACP, the 1911 pattern the Beretta M9 replaced as the U.S. service pistol.
- CZ 75 Pre-B and transitional pistols from Czech police and military service and CZ 85 pistols, double-action 9mm service pistols from the same generation as the 92. Our guide on how to identify a CZ 75 Pre-B covers the early guns.
The grid below updates by itself as pieces come and go.
Auto-Ordnance 1911TCAC6 .45 ACP Stainless Cerakote TruGlo Night Sights$649.00
Free ShippingCZ 75 Pre-B 9×19 Czech Police Surplus Grade A Matching Numbers Mirror Bore$569.00
Free ShippingCZ 85 9×19 Czech Surplus Pistol Pre-B Transitional$569.00The short version is on our Instagram. Watch it on Instagram.
General information for collectors, not legal advice. Suppressors are regulated under federal law, and state laws differ.
Common Questions
Is this Beretta the Vietnam-era Hush Puppy?
No. The Vietnam-era Hush Puppy was the Mark 22 Mod 0, a modified Smith & Wesson Model 39. This Beretta 92F with a KAC Snap-On suppressor uses the same slide-lock idea in a later pistol.What was the Hush Puppy pistol?
The 9mm Pistol Mark 22 Mod 0, a suppressed Smith & Wesson Model 39 with a slide lock carried by Navy SEAL teams in Vietnam. The nickname came from its stated purpose of quietly eliminating guard dogs.What does a slide lock do on a suppressed pistol?
It holds the slide shut when the pistol fires, so the action makes no noise, no gas escapes from the ejection port, and the empty case stays in the chamber. The slide is racked by hand for the next shot.What is the KAC Snap-On suppressor?
A Knight’s Armament Co. 9mm pistol suppressor. Early ones threaded on; later ones, like the example shown here, latch onto a specially machined barrel, in this case on a modified Beretta 92F. RECOIL gives its official issue name as the XM-9 and reports that the U.S. Air Force took 3,800 of them.Why does the KAC Snap-On have its own sights?
The can is too wide and tall to see the pistol’s sights past, so it carries its own: a bead front sight on the tube and a notch rear sight on the rear latch assembly.What are suppressor wipes?
Flexible discs inside some suppressors that the bullet passes through; in the KAC Snap-On they are polyurethane. They close in behind the bullet and slow the gas, which makes the shot quieter, but they wear with every shot and have to be replaced.How many rounds do the wipes in a KAC Snap-On last?
There is no verified fixed number. RECOIL says it depends on the ammunition and rate of fire, with supersonic loads wearing them much faster, and gives no round count; we have not tested ours.Sources
- Small Arms Review, “The Hushpuppy” (Mark 22 Mod 0) — https://smallarmsreview.com/?p=2735 (guard dog request and nickname, 1966–1967 development, 100 to 120 made for the Navy, 160/133/129 dB roughly converted, Model 39 basis, longer barrel, higher sights, slide latch with triangular tips locking the slide, manual repeater, Mark 3 suppressor with urethane disks, insert replaced after 24 shots)
- Wikipedia, “Smith & Wesson Model 39” — https://en.wikipedia.org/wiki/Smith_%26_Wesson_Model_39 (SEAL teams used the Model 39 or the Mk 22 Mod 0 Hush Puppy in Vietnam, slide lock, raised sights, purpose against sentry dogs)
- Dave Merrill, RECOIL, “Knight’s Armament XM-9, Snap-On Silencer” — https://www.recoilweb.com/knights-armament-xm-9-silencer-142421.html (Snap-On generations and gate latch, XM-9 name, 3,800 for the U.S. Air Force, wipes and expansion chamber, size, sights, slide-lock behavior on the test gun, Nielsen device and the 92F, wipe life and accuracy)
- Wikipedia, “Beretta M9” — https://en.wikipedia.org/wiki/Beretta_M9 (M9 adopted as the U.S. service pistol in 1985, replacing the M1911A1)