A “Made in U.S.A.” Uru SMG clone

It looks like the whole thing started in late 1980 or so, when the U.S. Government, within its Joint Service Small Arms Program (JSSAP), issued an RFP (Request For Proposal) for the conceptual design and fabrication of a 9x19mm submachine gun. Historically, the U.S. Armed Forces, in contrast to most other countries, had not relied to a great extent on SMGs, the then-issued gun of this type being the .45 ACP M3A1 ‘Grease Gun’ of WWII vintage. What was expected was the acquisition of limited quantities of an intermediate weapon of advanced technology and usefulness to fill the gap between the .45 ACP M1911A1 pistol and the 5.56x45mm M16 rifle. In fact, a mixture of foreign and domestic submachine guns had been purchased for use by special operations forces of all the services, security forces, armed vehicle crew members, and for the enforcement of laws and treaties by the U.S. Coast Guard. It was generally wanted to develop a supportable, very reliable and effective weapon by advancing the appropriate technologies associated with submachine gun designs, the RFP describing desired characteristics that were not entirely satisfied by the designs then available. However, the Government’s specifications were somewhat self-contradictory in that they asked for reliability and maintainability on the one hand and, on the other hand, they were requiring features which would overly complicate the weapon’s design. Some of them:

The 9x19mm weapon might be easily converted to .45 ACP caliber, and also be capable of functioning in the full- and semi-auto modes from both the open- and closed-bolt firing configurations, with emphasis on the closed-bolt mode. Manual selection between the two modes could be either with a selector lever or by changing the assembly procedures of the trigger/sear mechanism. A 400-to-500 rounds per minute cyclic rate of fire was suggested, at the same time that some interest in a three-round burst selector at 1,200-1,400 or higher rpm was shown, this option being considered only if the weapon’s reliability and controllability were not compromised. Some physical characteristics included a barrel length in the 150 to 200 mm range and an empty (no ammo or sound suppressor) weight of not more than 3.2kg (1.8 to 2.7kg preferred). Other required features included a collapsible, folding or telescopic butt stock, minimum 30-round magazine capacity (if possible, with its long axis parallel to the bore!), an integral base for commercial collimated sights (e.g. at that time Quick Point, Single Point, Instasight, Tascrama, etc.). Many other detailed items followed, but will not be included here to keep my notes adequately sized.

At that time (late 1980-early 1981), Saco Defense Systems Division of Maremont Corporation contacted a U.S. company called Frentex Incorporated which acted as a liaison to Mekanika Indústria e Comércio Ltda., the Rio de Janeiro-based company that was beginning to series manufacture the Uru submachine gun (http://www.thefirearmblog.com/blog/2017/06/15/brazilian-9x19mm-uru-smg-reloaded/). The idea was to see whether Olympio Vieira de Mello Filho, the weapon’s designer, might come with suggestions capable of meeting the strict  JSSAP requirements. It seems that some production examples reached the U.S. for a hands-on evaluation by Saco Defense, and at least two (a prototype and a production model) were submitted to highly-successful firing tests in Europe by Fabrique National Herstal in about 1981. It was no small coincidence that FN and Frentex were business associates, which somehow makes a Saco-FN connection apparent.

The Saco M683 submachine gun as shown in a picture published (“Jane’s Infantry Weapons”?) at the time of its introduction.

It just so happened that in 1983, Saco announced and started promoting its Model 683 submachine gun, which included the available granting of license production to other countries. Just a superficial look at it showed that it was, to all extents and purposes, an Uru clone, and I clearly remember Olympio’s WTF-type reaction when I showed him pictures of the weapon in the prominent “Jane’s Infantry Weapons” annual… I never knew if the promised legal sanctions were actually carried out by Mekanika at that time, and since no actual contracts materialized from the M683 affair, the whole thing fell into complete obscurity… until a spark of memory came to my mind when I saw that Corey R. Wardrop, Museum Curator of the Institute of Military Technology, in Titusville, Florida, was a colleague writer here at TFB. I vaguely remembered a 1980s article on the “six-eight-three” in a U.S. publication saying that the featured gun belonged to C. Reed Knight, Jr’s collection, and one thing led to another. Corey was kind enough to locate three of those Saco-made SMGs in the Museum’s inventory and was able to take the excellent pictures I’m sharing with you now. Thanks, Corey!

A Mekanika Uru “ghost image” is shown beside a Saco Defense M683, which gives a clear idea of the cloning process involved in the “Made in U.S.A” gun. (Bottom gun: Institute of Military Technology collection)

In a very concise analysis, the Saco Model 683 had the general Uru configuration to which some cosmetic changes were added. More evident were the retractable tubular stock, the slightly reshaped pistol grip, the longer trigger, the longitudinal ventilation openings (rather than orifices) around the barrel, the addition of a flash hider, and the light supporting structure for the plain optical (non-enlarging) sight. My surviving notes from that period show that both 25- and 32-round magazines were made, the gun’s loaded weight being in the 3.3-3.5kg range.

Left side view of the Saco SMG. Markings are “MODEL 683, CAL 9MM X19 – S/N XXX – SACO DEFENSE SYSTEMS DIVISION – MAREMONT CORPORATION – SACO, MAINE USA”. (Institute of Military Technology collection)

Right side view, stock retracted, bolt cocked at the rear. Identical (to the Uru’s) positions of the trigger and fire selector pins in the stamped lower receiver indicate that the gun’s internals were basically the same. (Institute of Military Technology collection)

The same goes for the positions offered by the re-shaped fire selector: “A”, rear; “SA”, top; and “S”, forward. Metal loop around the top receiver is for the stock sliding. (Institute of Military Technology collection)

The gun with the bolt in the retracted position and an empty magazine in place. The large pull-back magazine catch of the original Uru gave place to a smaller (push-in?) unit. (Institute of Military Technology collection)

The view through the simple optical sight fitted substantially higher on the gun than the original Uru iron sights (fixed rear aperture, front post). (Institute of Military Technology collection)

If imitation is the sincerest form of flattery, hats off to Olympio Vieira de Mello Filho, the Brazilian creator of the original Uru submachine gun. (Institute of Military Technology collection)

Ronaldo Olive

Ronaldo is a long-time (starting in the 1960s) Brazilian writer on aviation, military, LE, and gun subjects, with articles published in local and international (UK, Switzerland, and U.S.) periodicals. His vast experience has made him a frequent guest lecturer and instructor in Brazil’s armed and police forces.


  • TheNotoriousIUD
    • Samuel Millwright

      +1 on the k7

      Also, the koreans taiwanese and etc were so far ahead when it comes to using the armalite rifle upper and lower as the basis for any and every type of gun imaginable that most people don’t even know they did the majority of this stuff first!

      Daewoo also makes the k1a1 DI bufferless 5.56 with sliding “pdw stock”

      The K2 a long stroke piston bufferless 5.56 rifle with side folding stock.

      Then the Taiwanese have been doing short stroke piston guns for a long long time.

      And, yes kids, the Daewoo guns are AR based! Daniel E. Watters will be able to tell the story far better than me, but essentially the altered receivers are the result of a production license being denied or revoked or something after the koreans already had the TDP or enough of it to do the alterations and keep producing the new NOT A COLT M16.

      • TheNotoriousIUD

        I think TFB did a review of the K1A1 a long time ago.

        Its on my list too.

      • South Korea’s co-production license with Colt was for a specific number of M16A1, only for the use by the South Koreans. The South Koreans tried to cheat on these limitations on multiple occasions by making more rifles than allowed and attempting to export the rifles and parts. There is a 1988 GAO report on the subject titled “U.S.-Korea Coproduction: A Review of the M-16 Rifle Program.” It is available on the GAO website.

        • Samuel Millwright

          Thanks Daniel, i didn’t want to mess up exactly how the situation happened.

  • ShootingFromTheHip

    “A barrel length in the 150 to 200 mm range and an empty (no ammo or sound suppressor) weight of not more than 3.2kg (1.8 to 2.7kg preferred).”

    I find it extremely obnoxious not to include the standard measurements of these metric units. I could easily convert the units on google, but it’s the job of the writer to strive for an engaging, seamless a read, not to push the metric agenda on AMERICAN readers.

    • TheNotoriousIUD

      Ive been saying for years that TFB has a hidden metric agenda.
      I just hope no AMERICAN children were exposed to this.


      • Zebra Dun

        Metric system is clean, it’s easy to move a decimal point hard as heck to do conversions in the mind.
        I always like metrics.
        You just have to quit one and use the other, doesn’t matter which.

      • carlcasino

        Metric might be right for the scientific world. had it shoved at me during Nuclear training. I’m neutral. My campaign is getting rid of the Penny. cost 2.5 cents to produce and has no mineral value and is worth $0.006. Off topic I know but have to have something to rip about.

        • TheNotoriousIUD

          Based on our kids science and math scores we’ll all be speaking Chinese soon anyway.

    • Old Tofu

      learning is hard

      • Cal S.

        It’s not a matter of learning, it’s a matter of relation. Being raised with the Standard system means we know roughly what an inch and a pound is without having to try to mentally convert in order to relate it.

        Same with people raised with the metric system. They’d have to run through the same mental conversions if this article were presented in pounds and inches.

        • TheNotoriousIUD

          Some of those commies took our pound and started using it for money.

        • iksnilol

          Does the basic math make your head hurt?

          • Cal S.

            It’s more a matter of laziness. I mean, I rarely walk 1/10 of a furlong in a fortnight. More accurately, probably an acre or two a day, maybe less than half a dozen rods, more likely a stone’s throw or two…

          • iksnilol

            Then you walk too little, no wonder you’ve got heart diseases.

          • Cal S.

            Don’t let my avatar’s shape fool you…

          • Stephen Paraski

            I do a couple Hectares every day. They are great after coffee.

          • carlcasino

            Or 6 fathoms.

          • Zebra Dun

            Yup, especially conversion of Arshins.
            “I think I spelled that right”

        • Zebra Dun

          Worked on a Survey crew once long ago in my youth, never realized how hard distance measurements was!
          Yup, I was the rod and chain man.

        • carlcasino

          Travel overseas and the money conversion will drive you to pay off the national debt of lower Mongolia without knowing it, or tipping the Taxi driver with that big quarter that is worth $2.50 US.

    • iksnilol

      No offense, snowflake, but mm and kg are the *world* standard. Get with the times, old man, you’re streets behind.

      Get that commie “standard” s*** off the free internet!

      • Cal S.

        So was Communism at one point, but now most of the world has gotten over that.

        • iksnilol

          But inch and pounds were measurements used by the commies.

          Thus American Standard Measurement = Stealth Communism. So obviously you and everybody else pushing that backwards system are commies and should be summarily executed for high treason.

          EDIT: Communism was never the world standard, for your information. You wish you pinko commie.

        • Zebra Dun

          Half the US is still stuck on it like a petard.

      • Alahahahah

        So was esperanza; the globalist ploy to destroy individual cultures

        • iksnilol

          Not really, what’s wrong with everyone having a unified secondary language?

          • Samuel Millwright

            We do, it’s called English LOL

          • iksnilol

            Not really, plenty of people don’t know English. And English itself is rife with inconsistencies and unneeded complications.

            Esperanto is simple, adaptable and easy for everybody to learn whilst being flexible.

          • Alahahahah

            You do realize that your comment simply screams ‘Statist’ don’t you? Oh wait, it’s obvious you don’t, or are good with totalitarian violence.

          • iksnilol

            Not really. Nobody is being forced to use it, and it doesn’t take precedence over the native tongue.

      • ShootingFromTheHip

        Get the hell out of America, commie!

      • RazorHawk

        huh? No it isn’t. Europe is not the world. Many countries and societies have not adopted the metric system. The firearms industry is a good example.

        • iksnilol

          “many countries”, literally only three countries don’t use metric system, and those three are the US, Burma and Liberia. So get out of here with your alternate facts.

    • Barba76

      Von Braun the one who put a men at the moon… metric… world wide use ammo 7.62x51mm and 5.56x45mm… the metric sistem my american friend is in you… sorry for the bad news… 😀

      • DangerousClown

        Uh, okay.

      • RazorHawk

        Of course Von Braun would use the metric system, he was a German. Ammo weight is still measures in grains, and velocity in feet pe second.

      • Zebra Dun

        Oh I remember Von Braun, “I aimed at the Stars, but occasionally hit London”

    • Maths are hard

      U.S. dollar is a base 10 system just like metric.

    • Joe

      Common sense solution: use both, every article. Both systems are international, Metric per European Standardization to include most of the world, American Standard worldwide due to cultural influence and trade.

      • carlcasino

        Worked on a Drill rig overseas a few millinia ago and the mixture of US & Metric caused a ton of problems.

    • Samuel Millwright

      I’m an AMERICAN (I can use all caps too lol) who designs and builds firearms and custom parts for them as well as my own tools and other fun stuff… Guess which system of weights and measures more than 75% of my tools etc are in / i prefer to work in?

      Hint: not SAE

      Guess which system the M16 Technical Data Package is in?

      If you’re too lazy to learn metric and or believe that the world somehow owes you something, and you’ve bizarrely chosen to cash in this debt on not having to learn metric….

      Fine, whatever floats your canoe… But don’t pretend like metric measurements are some commie plot that all real Americans must resist, because then you just make all of us seem stupid and paranoid.

      • ShootingFromTheHip

        Incorrect. It’s such a specious, BS argument that since the rest of the world uses metric, it makes sense to refer to metric measurements in American publications. By your logic, it would be forgivable to include Mandarin terms or phrases in American publications, since Mandarin is the most spoken language in the world.

        You have to be an imbecile to make the argument that American readers should be burdened with metric conversions when they’re consuming American media. It’s not a question of being smart enough or being too lazy to look up the conversion. The fact of the matter is that SAE is the customary unit of measurement in America, and referring to metric units to American readers is unnecessarily obnoxious, pretentious and out of touch with reality.

        • roguetechie


          Dude…. Ever wondered why English is such a crazy language to learn?

          It’s because we have literally been adopting words, concepts, whole phrases, and et cetera from any and every source for something like a thousand years!

          So… Yeah…. Just learn metric and STFU because learning new stuff, adopting better systems processes etc constantly, a lack of fixed ubiquitous traditions and or a homogenous static culture, and constant changes evolution and growth ARE AMERICAN TRADITIONAL VALUES!

      • RazorHawk

        And if you reload, your bullets are measures in grains, and velocity in feet per second.

        • Samuel Millwright

          Yup lol… Except when they’re not, but that doesn’t count

        • Ninoslav Trifunovic

          I’m from Europe, and I do reload. And yes, I use grains because it’s easier and more accurate that way. And that’s what most of European reloaders do. But I’m pretty sure that not a single one of them use fps. Using fractions of an inch is real PITA when compared to millimeters.

  • FWIW: I seem to remember seeing Mack Gwinn credited with working on the Saco M683.

  • Vincent

    Would have loved to see Olympio’s reaction, must’ve been quite the sight!
    The US Uru certainly looks like a good deal. Simple, compact and reliable. Though I suspect that with how much that magazine sticks out and how the optic is about 12 feet off the top of the receiver, it would have been pretty weird to use if you have to go prone.

    I would love a copy of it.

    • Given the straight-line stock configuration, they didn’t have much of a choice but to raise sight height…

  • Joe

    I know Aimpoint existed at the time, but that sight is rather interesting.

  • CalAnon

    I’d love to see some high quality images of that tasty little sub-gun.

  • Stephen Paraski

    Great stuff Ronaldo. Me and my Compadre, Jorge Rodolfo Tomatti, Ex Argentina SF are traveling “South” next month to see what we can see.

  • Zebra Dun

    Lets see, the Swedish K was popular while I was a young man yet the M-3A1 was the standard, with a few Uzi which were highly valued.
    Eventually settling on the HK MP-5.