In the early 1960’s a former OSS operative and mercenary Mitchell WerBell III set up a company dedicated to the development of cheap and efficient sound suppressors for automatic weapons.

WerBell had joined the US Army immediately after the Second World War began, serving briefly as a second lieutenant with the Signal Corps and then volunteering to join the newly formed Office of Strategic Services (OSS) in 1942. The OSS was technically part of the US Army, so it was more of an assignment change than a change in service branch.

WerBell became an expert in guerrilla warfare fighting in Manchuria, Burma and Indochina during which time he became familiar with the suppressed firearms often used during clandestine missions. After the OSS was disbanded in September 1945, WerBell returned to the regular army as a captain but didn’t last long. He resigned, finding the routine of commanding an infantry company dull. There is a vast difference between peacetime and wartime military.

During the 1950s he worked in PR and advertising before deciding to launch his own manufacturing company specializing in sound suppressors for firearms.

WerBell founded SIONICS Inc. in 1966 and specialized in building clandestine weapons and counterinsurgency equipment for the military and Central Intelligence Agency. The name SIONICS was an Ian Fleming-esque acronym of ‘Studies in Operational Negation of Insurgency and Counter Subversion’. If it sounds a bit dramatized, it was.  WerBell began work designing suppressors for the M16 and M14 applying for his first patents in January 1968.

SIONICS also specialized in adapting existing firearms to take suppressors these included High Standard Pistols, Remington bolt action rifles, Ruger 10/22s and the Smith & Wesson M76 Submachine Gun.

Smith and Wesson M-76 SMG

The SIONICS M16 suppressor was made up of a tubular housing filled with a series of entry, suppression and resonant chambers. The suppression chamber contained sets of helical metal baffles, this design did not utilize wipes. It attached to the rifle’s muzzle via a set of internal threads.

The suppression chamber was separated from the entry chamber by a stepped axially apertured partition. The suppression chamber was ported to allow propellant gasses to enter the helical baffles. The design’s baffles were placed inside the housing alternately opposing each other to avoid the free flowing of the captured gases. The patent explains that the suppressor’s housing varied in thickness in an effort to further deaden sound vibrations. WerBell’s patent also explains “that more than five suppressor units [the helical baffles] may be used if desired” to increase the suppressor’s effectiveness. He notes, however, that testing with just two oppositely wound baffles achieved satisfactory results.

WerBell’s second patent mirrors Maxim’s work by stating the design could also be used as both “silencers for use in conjunction with firearms and as mufflers for internal combustion engines.” His second patent includes some entry chamber variations but retains the helical baffle system. WerBell’s third patent submitted in December 1970 and granted in January 1973 covered the incorporation of a relief valve system to reduce blowback pressure when fitted to rifles and machine guns chambered in 7.62x51mm.

Designed for the M14, SIONIC’s M14SS-1 was 12.75 inches long and 1.7 inches in diameter. It weighed just under 1kg. The early production models used the patented valve system but these suffered failures when the valve acted as a heat sink melting the valve’s spring. The valve’s could not withstand the high gas pressures and a simpler relief port was eventually designed. The majority of SIONIC’s M14SS-1s were purchased by the US Army with a number also being purchased by the US Navy.

Extensive testing and field testing (with 40 M14SS-1’s sent to the 9th Infantry Division in Vietnam for combat evaluation in 1969) led SIONICS to also develop the MAW-A1 model (Moderator Automatic Weapon – Alteration 1) for the M16. These were frequently used by US Special Forces in Vietnam for long range reconnaissance patrols and clandestine missions. The MAW-A1 was also initially made with the patented relief valve but issues with the M16 also led to the introduction of a more reliable relief port. The MAW-A1 proved to be a reliable and effective design, well liked as it was rated for full auto fire. Many of SIONICS’ suppressors had a rated life span of six months or 200 rounds before the suppressor’s efficiency began to deteriorate. At this point the suppressor could be taken apart and the internals such as the helical baffles could be replaced. SIONICS also developed a series of pistol silencers as well which were used by US Special Forces, often paired with High Standard, Ruger .22LR pistols or with Smith & Wesson’s Model 39 (Hush Puppy).

In 1969, Gordon Ingram, famous for his earlier machine gun designs such as the Ingram Model 6, joined SIONICS Incorporated to begin manufacturing his new compact submachine gun design. WerBell had seen the potential of Ingram’s new M10 design and hired him as chief engineer to oversee production of what would become the MAC-10. Ingram had begun work on the M10 in the mid 1960s was chambered in .45 ACP and 9mm but had been unable to find backers. The weapon was small – just 11 inches long, it used a straight blowback operation and was made from stamped sheet steel. It had a telescoping bolt and a combined pistol grip/magazine housing. Firing from an open bolt it fed from 30 round surplus .45 ACP M3 magazines or 32 rounds of 9mm magazines. The suppressor tubes were covered in Nomex-A, a heat resistant polymer to enable the tube to be used as a grip point.

In 1970 the SIONICS and an investment group, Quantum Corp., was incorporated into larger company Military Armament Corporation with WerBell becoming the new company’s president. The new company began production of the MAC-10 in 1970, each gun was threaded to enable it to be fitted with WerBell’s suppressors. The design used was a two-stage suppressor that utilized two sets of WerBell’s helical baffles. Simpler less sophisticated single-stage suppressors were made later that used polymer wipes rather than baffles.

image

(above) An ARVN officer fires an unsuppressed MAC-10 while WerBell looks on.

The MAC-10 was used in Vietnam by both US Special Forces units and CIA case officers, it was best paired with the subsonic .45 ACP round which also had a slightly slower cyclic rate making it more controllable. The suppressed 9mm versions using supersonic ammunition did not slow the bullet sufficiently to prevent a subsonic crack, however, it did suppress the sound of the round leaving the muzzle.

In 1974 the U.S. State Department barred foreign sales of submachine guns with suppressors. This severely curtailed Military Armament Corporation’s sales, attempts were made to sell the MAC-10 without the suppressor and with a longer fixed barrel. However, this removed the gun’s strongest selling points; its compact size and quiet firepower. The Military Armament Corporation declared bankruptcy in 1975 and the company ceased to exist in 1976.

I found the MAC-10 to be difficult to control. The silencer, wrapped with an anechoic coating could be held as a means of control when firing, but it was twitchy because the only thing connecting it to the firearm were the threads on the barrel and at times the silencer metal would actually bend, sending .45 ACP rounds through the casing. The MAC-11 was much smaller and had a very high cyclic rate, but it was loud and even more difficult to control. By the time the company went out of business, there were competing options, UZI being foremost among them and it was a state-backed industrial product where the MAC-10 was not.

My favorite MAC-10 story involves a planned cartel assassination of a member of a rival cartel, using that weapon, while riding a motorcycle through Guadalajara, Jal. They decided to do a dry run near the golf course but did so with a fully loaded magazine, which left the cartel shot caller in the (simulated target) car, dead, and a bystander who had an early start time on the course dead as well. The bystander was not “innocent”, being a high ranking member of the cartel. The shooter, who crashed his motorcycle because of uncontrolled recoil was promptly executed, while trying to stand after the accident. Cynics called it a three-fer.

28 COMMENTS

  1. I have zero practical experience with full-auto, so I defer to your opinion on the MAC-10.
    Has a cool name, and Warren included it in a song, so that has to count for something?

    -Kle.

    • The MAC-10 was an evolutionary step that ultimately failed, but at the same time demonstrated the need for a compact SMG. The Uzi beat it out fair and square and then the H&K MP-5 came along and became industry dominant. There are different trigger groups for the MP-5 that allow for selective, semi-auto, burst, full fire, but the key with all weapons of that class is being able to double tap. The MP-5 allowed for an easy double tap wherein the MAC-10 was more of a spray and pray weapon because it was not shoulder fired. It could be, but you didn’t.

      Then came Heckler & Koch’s MP7, chambered for the HK 4.6×30mm armor-piercing cartridge. It was designed together with the new cartridge to meet NATO requirements published in 1989, which called for an SMG-type weapon that had a greater capacity to defeat Kevlar body armor than pre-existing submachine guns using conventional pistol cartridges such as .45 ACP and 9×19mm Parabellum.

      The last of this line that I have personal experience shooting is the MP7A2, and it makes the older designs such as the MAC-10 really look obsolete.

      • What really set the MP5 apart from all the other sub guns at the time was the fact that it fires from a closed bolt making single shots or semi auto fire a great deal more accurate. Not so easy to do with open bolt guns.
        McQue was the first time the public got to see the Mac10. Even though the Duke was deferred from the draft (age,kids) I read he did have some dealings possibly with the OSS. I wonder if there was a connection to WerBell or Ingram?

        • I have no idea whether or not there was a connection.

          Open bolt SMG’s have inherent problems and now they all fire from a closed bolt. They’re more accurate and there is not a lag between when you pull the trigger, the bolt goes home and the first round goes off, the action is kept cleaner, they’re more accurate, etc.

          • Larry. I never liked the Swedish K because of its firing from the open bolt position. Too much risk of getting crap in there just when you needed it most. Strangely, a lot of people liked it. No accounting for taste I guess, although I think some people only liked it for its spook connotations. Much preferred the Sterling if I wanted a suppressed weapon. Although also firing from the open bolt position it had a feature for cleaning out any crap, giving it much more reliability.

          • You wound me. The K fired from an open bolt as did all SMG’s in that era. There is only a spook connotation TODAY. Back when the spooks tended to carry them – and the Navy Thompson – they were simply the SMG of choice because they worked. The Sten/Sterling SMG, which saw use up through the mid 1970’s was not as robust in my opinion. My biggest gripe is the magazine placement. They were not as compact as the Gustav and were more prone to jamming.

            The last time I had a Sterling jammed in my face was near the Belfast Airport circa 1977, and it was carried by a RUC type with an attitude. He had my respect – well the Sterling did.

          • Sorry my good friend. I did not mean to wound you. Please accept my sincere apologies. Agree with you about the Sten not being robust, although I disagree about the Sterling. Yes, I agree that the Sterling was not as compact as the Swedish K. Disagree about the jamming though. Agree that the spook connotation is a recent thing. What I meant was that they were the preferred weapon of the CIA, at the time, and that some people liked that association. We will also have to disagree on the magazine placement. At least with the Sterling you could fire it comfortably from the prone position whereas, with the Swedish K, you had to raise yourself up slightly.

          • Firing ANY SMG, with the exception of the Sten/Sterling prone is challenging and that is certainly an advantage of that model. The new MP-7 is small enough – a true machine pistol – with a light enough recoil that you can pull off prone firing. But it took sixty years to get from the Sten to the MP-7.

            You could argue that the Uzi could be fired prone, effectively, I guess. Magazine placement even with the Uzi, gets in the way.

    • X2 on both accounts, Ed. Weapons evolve based on experience and they are still evolving. The biggest recent change is the US Military decision to deploy with silencers on its rifles. A long time coming.

  2. I have no experience with the full auto version and have only handled, but not fired, the semi-auto. I have never felt the urge for one of my own. The TEC-9 is also something that doesn’t tempt me. I have seen neither at the range, but then I usually work the 100 yard line.

    • A friend of mine had a TEC-9. My only question to him was, “why”? Not the best semi-auto 9mm out there, too large.

      He liked the look.

  3. Knew a guy, many years ago, who had been in Laos in the late ’50s early ’60s.
    He had a pair of MAC-11s from the ’70s that hung in his closet in a double harness.
    I do not know if they were the real deal Class 3.
    I am sure he is long dead.
    Don’t mess with old guys bearded wearing a Hawaiian shirt and cut-off jeans…you never know where they have been and what they have done.

    • I’m sure that they were real if he picked them up in Laos. I don’t think that they made semi-auto MAC-11’s? Maybe they did, but why (see comment about TEC-9 above)? Their only use is as a close range hose. They have a higher cyclic rate than MAC-10. The MAC-11 is spitting them out at 1,200/min. They came in .380 and 9mm.

      Better to leave messed up looking old men alone. Just as a general rule. That goes for women as well (not messed up looking). Brig carries a 1911 and a cattle prod in her purse. Best be polite, tip your hat, and move on.

  4. An acquaintence of mine had a Real Deal MAC-10, with all the goodies. He said the supressor was quite good, and when firing subsonic full auto, the action clacking and banging made more noise than came out of the muzzle.

    He had a briefcase the silenced weapon fit into, with a remote trigger control. He called it a “Hit Kit”, and said it would be amazingly effective in crowds, as nobody would know where the shots were coming from.

    • The one I had would fire from a briefcase, too. But you’d spray everything if you fired it like that. More of a daisy cutter than a precise weapon for assassination. It was quiet silenced but not as quiet as an MP-5SD2, for example. However, we’re speaking of different generations of firearms.

  5. The guy with the MAC-11s could not have got them in Laos because he was there before the MAC-11 was made.
    As I recall Cobray made a semi-auto model after they took over the company in the late ’70s?
    He was a very different guy and worked doing undercover stuff. He alluded to doing things for the .gov after Laos/Vietnam, but no specifics.
    He infiltrated Earth 1st as an investigative journalist. His book on the radical environmentalists is out there somewhere. I don’t recall the title.
    I have met and worked with some people who have told be some stories that I found far fetched only to discover years later that they were true.
    He was USAF in Laos and told me he was the only survivor from his team. He said they had been captured and he was forced to watch as the other members of his team was beheaded. He did not elaborate, but was explaining his hyper vigilance to me. How he survived I do not know. He had PTSD from some of the experiences of his formative years.
    I later learned about White Star and guessed he was involved in refueling at secret bases in Laos. Don’t know for certain.
    I do know that while I worked with him (he was in his 70s) he set up an interview with a county pshycologist about a local drugs, sex, guns, and gang scandal. He called me from the parking lot where she had set up the meet. He told me that she shoved a .45 Glock in his face and screamed that she was going to f’ing kill him.
    He disarmed her. She lost her license and did some time.
    He had some pretty good computer access and was able to do research not available to most people due to firewalls.
    Interesting guy.
    That’s been twenty years ago, so I doubt he is still amongst the living.

  6. BTW
    You mentioned Brig.
    She can verify the story of the county psychologist, the drugs, sex, guns, a gangs, and the disarm by the journalist.
    ‘Cause she lived there when it went down!

    Oh, and Brig used to shoot at the same club of which I am a member before she went to the PNW.

    Several.years ago I was at the range and there were three ladies of a certain age shooting in the next lane over.
    One of them had a stainless steel S&W ten-shot .22 LR revolver with speedloaders.
    She asked if I would like to try it.
    Well duh!
    It had the smoothest double action I have ever used.
    She said her husband had had it tuned up for her. He was a competetive shooter.
    I have long suspected that Brig was one of the three shooters that day.
    And I saw no evidence of an electric cattle prod, but one of ladies did have black gloves on a riding crop clamped under her left arm.

    • I’m persuaded that Brig carried a cattle prod for point defense. I don’t know if she still does, but I wouldn’t want to test either Brig or her buddies, all of whom take their personal defense seriously.

  7. An area where I have zero experience and knowledge. I seem to remember reading suppressors distort/diffuse muzzle “bark” in a way that makes locating the source more difficult. You still hear it but have a much harder time locating the source.

    • They’re useful. A proper combination of weapon, silencer and ammo (subsonic), well engineered, means that you only hear the action work. No noise beyond that. And if you’re really serious, your pistol is engineered to fire a single shot, rather than using a machine gun. They’re damned near silent.

  8. Didn’t know about WerBell, interesting. Recall some fun hours at the range with a Sterling, and I thought they looked cool. Mind you, most guns look good to me.

LEAVE A REPLY

Please enter your comment!
Please enter your name here