Microtech Small Arms Research (MSAR) STG-E4 Rifle

Microtech Small Arms Research went out of business a while ago, but their website is back online and the new owners are bringing an updated version of the STG rifle to market.

The STG-E4 is patterned after the Steyr AUG. It will be available with either .223 or .300 AAC BLK barrels. The fluted barrels are available in 16.5”, 18.5” and 20” lengths. It uses a standard AR-15 magazines.

MSAR used to be a strange company. They got little press from bloggers because they put up a big notice on their website saying that everything on the site was copyright and they did not give permission for it to be used in any way. I emailed them once asking permission to use photos on TFB, but got no response and so never wrote about them.

[Hat Tip: Aftermath Gun Club]

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Mechman

    Tempting, but given that one of the highlights of the blackout as a round,at least to me, is that you can use an easy to modify rifle (AR-15) as a base for building one. I already know how to hold an AR-15, I already know the weight and balance, and I can easily reconfigure one to match what I prefer as far as trigger, grips, optics, stock, and handguards.
    Changing to a pricey bullpup with a fixed stock, non-upgradable trigger and stock, and a folding foregrip instead of a bipod mount kind of ruins the appeal.

    • Point taken, however some people really prefer a bullpup. Of note, there are quite a few trigger upgrade options. Aside from the RAT Worx offering both Small Arms Research and Shotgun News often feature ads for different AUG & MSAR trigger upgrades.

      • noob

        Also, there’s a fair bit of value added in this MSAR STG-E4 offering that you’d have to buy as add-ons to an ar-15

        7 o’clock and 11 o’clock rails for canted optics and lights (and I presume symmetrical rails on the other side)

        Ergonomic stock that has a nicer curve and buttplate than the normal M4gery collapsable stock.

        Ambidexterous magazine release (okay, I kid on that one. It’s only ambidexterous if you mean it’s easy to slap with a magazine from either hand).

    • Julio

      Aside from trigger upgrades, Ratworx also do rail systems that let you mount a bipod as well as a vertical grip. The basic points stands, however: unless you really like bullpups why would you exchange the infinite variety of the AR platform for the configuration constraints of an AUG? As for the resurrected MSAR, I can see it would be neat to be able to switch out your standard .223 barrel for a suppressed Blackout barrel. On that note: are MSAR’s STG barrels compatible with Steyr AUG receivers?

      • There was a whole cottage industry popping up – small-time guys with CNC machines making all sorts of neat tricks for the MSAR, AUG A3 and AXR before they all either went out of business or got pulled off the market.

        As for the barrel compatibility, no. MSAR went out off their way to change a few things to make their parts incompatible with Steyr’s, and this was one of them.

    • Consider this: with the AUG quick-detach barrel design and the design of the .300 round, all you need to switch calibers is a separate barrel. The gas system is integral to the barrel assembly, so it could be tuned for the pressure curve of the .300 round. Your bolt and magazines would stay the same.

      • Mechman

        But with the AR quick detach upper design and the .300 round, all I need to switch barrels is to buy parts that would cost me less than buying a brand new AUG, and I can have different optics mounted for each barrel to adjust for the different ballistics without having to readjust the scope zero.
        While a cool design, this just doesn’t add anything particularly useful that you can’t already get cheaper.

      • Cymond

        I agree with James, swapping barrels on the AUG is very fast & easy.

        Mechman, your proposed system isn’t exactly cheap if someone is using good optics. Assuming an upper costs at least $600 and an optic is another $600, that’s at least $1200 to have a spare upper. Of course, I’ve seen 300 BLK uppers that are $1200 without optics. Personally, I’ll rerzero for that kind of cash.

  • Sian

    Maybe the new MSAR will be a bit smarter about web buzz.

    M16 magazines and .300 BLK capability? I am somewhat interested, especially since they’re keeping the quick change barrel capability.

    • Other Steve

      THAT’s the good thing with this gun and a 300blk barrel. I’m skeptical on the suppressed noise levels to the shooter, but having a quick change barrel system makes it a lot less of an investment to get into 300blk.

  • Munkfish

    I have one of MSAR’s earlier versions of the rifle, before they got rid of the forward assist. I’m glad to see that the E-4 will be back in production, it’s a neat gun!

  • Tan

    I already have an STG E4. Is this supposed to be a new product, or do I just own a super-secret prototype?

  • matt

    Weren’t they designing a pocket pistol? I think it was called the Archangel or something. I wonder if that is ever going to come to market.

  • higgs

    Needs a few more rails….

  • Raoul O’Shaugnessy

    Shame about MSAR….in a world of yet-one-more-AR15-maker they actually had a product that was different from everyone else.

  • Nater

    I’d rather have a real AUG A3, unfortunately they’re not being made anymore. At least not for civilian sale.

    • Vek

      Steyr continues to manufacture and sell vicilian versions of the A3 in the US.

      this site carried an article last year about how Steyr was beginning to import them again.


      May 30th, 2011.

    • bob

      Nater, the AUG A3 is being reintroduced to the U.S.civilian market in the fall of 2012 as Steyr is tooling its factory down in Alabama for it right now. I think the MSRP for it is going to be around $2000.

  • Nicks87

    Why is it so hard for firearms manufacturers (or anyone) to make a reliable, modestly priced bullpup?

    I just dont get it.

    Maybe Charles Daly will come though with the Tavor but I doubt it.

    • El Freddio

      I guess it’s because everyone is in love with their ARs and AKs.

    • Chase

      I love the aesthetics of the modern AR, but the Tavor looks beautiful too. I’d definitely buy one if it had a 20-inch-long barrel.

    • charles222

      Bullpups are somewhat more mechanically complex, is the main reason a cheap, reliable one hasn’t happened yet. For every AUG or Tavor, there is an L85 :p

    • Julio

      I almost hesitate to ask, but is there a reason no one has mentioned the Kel Tec RFB here?

  • Curzen

    Given how guns sell like hot cakes it speaks volumes if a company goes out of business.

    • evilskinnybroad

      I believe there was a divorce between the couple that owned the company…divorces can throw *anything* under the rug.

  • Jesse

    What they need to do is produce the 9mm version that uses Glock mags that MSAR was working on. I’d buy that.

    • Other Steve

      I like the idea I suppose…. Especially for states that do not allow or people that do not want to deal with NFA/SBR stamps.

      A MSAR in your prefered pistol cal would be like having a 10″ AR in the same cal without the stamp. I guess since I have SBR 9mm carbines, it’s not that big of a deal to me. I do see the appeal though. It would be nice if they trimmed up the design a little for a pistol caliber version.

      Make a bullpup 9mm carbine with an integrally suppressed barrel and I’d be really interested. But then there is the issue of your ear being right at the action again, so, I’m not sure this would be a great idea.

  • G3Ken

    Bullpups are cool and surely have their advantages. The thing is, people use whatr they’re comfortable with. For most it’s some variant of the M-16/M-4 family, some swear by the M-14. I’m a G3K guy, although there are deinitely a number of things I would love to change on it. e.g: hold open after last round, better mag release, ergonomic improvements. Still, it’s what I practice with most.

    How much trigger time do any of us really have with a bullpup vs. our “regular” rifles?

  • PLUS

    Many rifles have .300BLK versions recently. Why this cartridge have been so popular now?
    Does it has really good ballistic performance or price is cheap?

    I’ve heard that it’s made to reach 7.62×39’s capability but also fit AR-15’s mechanism.It also does well with silencer.

    Are these true?

    • Other Steve

      Yes, it’s pretty much 7.62×39 with better BC. Fits in an AR to 30 round capacity reliably. Doesn’t break bolts and or have questionable mags like x39 conversions. Suppresses better than x39, 556, 6.8. Has a wide selection of bullets and brass for re-loaders. And goes from 110gr-240gr+.

      It’s not cheap though. Plinking ammo at best is .50 a round. Subsonics about $1 a round. Expanding subsonics are even more expensive and rare, limited to reloaders.

      It’s a very nice idea and effective for the ranges most people ACTUALLY shoot. But is a supplement to 556, not a replacement.

      • PLUS

        Thanks, so this cartridge can be reloaded cheaper and easier than other ammunition right?
        Besides, you say”ACTUALLY shoot”, did you mean combat or self-defence shooting?

      • Other Steve

        Nothing about 300blk is cheaper than 556. Every component is more expensive…. Except primer I guess, powder is a wash.

        The distance spoke actually ARs like 0-300yards.

  • Peter Ball

    Keep it under $990 and I may just “pull the trigger” on it. Anything above that and you might as well stick with AR/AK systems.

  • John Doe

    I’ve been looking at a .300 BLK AR, but this is much cooler. I’ve always wanted a bullpup rifle, and the ability to take advantage of my preexisting stash of STANAG mags is great. The AUG magazine may be better in terms of reliability, but it won’t be as good to civilians that already have a lot of AR mags. Would I like another AR? Yes, but I like mixing it up more.

    I’ll sign up for one please.

    • Other Steve


      There is nothing wrong with the AUG design, however, it is not a great suppressed platform. The action works and more specifically regulator dumps right at the shooters ear, this sounds like a pretty loud POP when suppressed.

      I don’t like AR’s suppressed even in 300blk as the action is still loud. Not unsuppressed loud, but the action makes more than a little noise. For fun take an AR, cheek it up, then release the bolt. Hear that? Now double that volume it for an approx of a suppressed subsonic shot. After a few rounds it’ll become unpleasant unless you have hearing damage already.

      So, to the point, the AUG does not work very quietly to the shooter when suppressed. You’ll pretty much NEED at least a strong side ear plug in. Just an FYI.

      Personally, I won’t shoot semi-auto rifle without at least plugs in anyhow. So I’m good to go with the AUG suppressed. 16″ 300blk in a ~11″ AR length package is pretty cool.

      • noob

        Well the Austeyrs that the Aussie army uses have a GR setting that cuts off the gas entirely.

        That would turn the weapon into a straight pull bolt action if you want really quiet operation.

        Also, “Right next to your ear”? the piston and regulator assembly is close to the vfg. you can actually burn your thumb on the exhaust if you fold the grip of an austeyr up and then fire it while holding it in a thumb high on the support hand.

        In comparison, the tiny exhaust ports on the AR-15’s bcg are visible when the ejection port dust cover are open.

      • John Doe

        I don’t want one because it’s practical. I want one for the same reason I want a suppressor or an AR. Because it’s fun and cool.

  • Doug

    I was warming up to MSAR just before they croked. I was also looking forward to their bullpup pistol caliber rifle, but they never produced it as far as I know. I think they could’ve made a bigger splash into the market with that one. I didn’t realize that they wouldn’t allow any press, that’s just stupid.

  • Other Steve


    The 300blk barrel only comes in 18.5″ ??? Way to pretty much make sure factory subsonic loads are going to go trans or supersonic.

    That makes no sense at all. 300blk is designed for a 16″ barrel, the sweet spot is 16″, factory ammo is designed for it… Why would they do this?

    • Vitor

      Are you really bitching about a barrel being 2.5″ longer in a bullpup? As if the extra lenght would make the round weaker.

      • Julio

        Vitor, the point is you can run the .300 BLK with either subsonic or standard-velocity loads. With the latter there’s no problem, but for many the primary appeal of the cartridge is its subsonic performance. Subsonic ammo is loaded to be reliably subsonic from a 16″ barrel, so if you add 2.52 to the barrel the velocity gain will mean that your subsonic loads are no longer subsonic, and that the bullets exiting the barrel in the transonic band may also no longer stabilise properly. Neither of these is good.

  • RickH

    I sold my AUG back in 1990, and I still kick myself for doing it. I was interested in the Microtech when it was introduced, but from user reviews of it I never knew if it was “just as good as the Steyr”, or “a piece of crap”. So any owners or former owners here? I would be interested in some opinions.

    • Spade

      I’ve got one of their later model AUG clones that takes AUG magazines. I’ve got their AUGA1 like scope and the rail. I got the scope because I always wanted an original AUG in green. And now I have it. Need to get a 20″ barrel though.

      It’s light, shoulders nicely, shoots well. The cocking handle can be a little stiff and with a scope or rail the ability to lock it back is pretty useless. I’ve never had a problem with mine but haven’t put too many rounds through it.

      Anyway, I like it. Plus having one removed my desire to own most, if not all, rifle caliber SBRs. Since my AUG is shorter or almost as short without being NFA.

  • Although I am an authorized dealer for Microtech (TFB actually featured a video review I did on the Navy Seal Scarab OTF knife back in 2010) I know little about the gun side of the business since I deal exclusively with their knives. However, they have been hitting home runs with their production knives and custom knives lately so I would only expect some really great stuff coming soon.
    As far as getting in touch with them; I call their main number daily and always get someone to speak with. This was not the case back in 2009 – 2010.
    I am looking forward to seeing these new guns and I’ve always been a fan of this design.
    And as someone mentioned earlier, I remember the Archangel preview; I sure hope they get around to that one.

  • JAR

    I bought a MSAR STG-556 several years ago when the E4 was being released and the STG-556 was going for $1,000 or so. It’s been a reliable range toy and handy to throw in the back of an ATV or the floorboard of a truck, and if you take the barrel off it fits in a camping backpack.

    After 1,500 rounds or so the barrel bushing started getting a little wobbly and accuracy went downhill, but Ratworx has a cheap little allen screw fix that tightens everything up at the expense of the quick-release barrel, which is pretty much just a party-trick anyway.

    As far as accuracy, the “standard” (I think most folks opted for the rail) AUG-style 1.5x optic is clear and holds its zero, but with such low magnification it was always hard for me, a very average shooter, to get a consistent sight picture at 100 yards. For the first 1,000 rounds, before the barrel bushing went wonky, I could sometimes put a magazine’s worth into an inch square at 50 yards, but was doing good to get 4-6 MOA at 100. I’ve not tried to shoot for a good pattern at 100 yards since the Ratworx bushing fix. It’s my main plinking and field gun now, having displaced my Mini-14, and I’ve got other toys for range work.

    Takedown and cleaning are dead-simple, and the ergonomics work for me. In about 2,000 rounds I’ve had maybe a dozen FTFs; mostly with Hornady brass-cased ammunition and always with the live round bent in the middle at 45 degrees. Never did have a jam with the cheap PMC that’s been my rifle’s main diet all it’s life, but something in the feed ramp area likes to put a little gouge on the bullet and brass. I can’t feel or see anything in there that’s doing it, but so far I haven’t really worried about it.

    All in all, I consider it a good purchase. I’m happy to see that a new owner is taking up the project.

  • drew

    I own ars sig 556s a 516ar from sig but still one of my favorite rifles is my msar stg556 i can shoot one handed its balanced so rite n taking a barrel off ina second is a definate plus the trigger u think is clunky until u shoot one then theres no problems i highly suggest this rifle if its as good as the original my 2 cents

  • Sulaco

    I just recently bought a used MSAR E4 and like it alot, shooting it at 50 yards with an optic places it very close to my favorite carry rifle, but what I would not give for a parts repair kit! Last one I saw on Ebay went for upwards of 900 bucks. I hope the new MSAR starts selling them again soon.