Bufferless: The Serbu SU-15 Upper Receiver Group

Serbu Firearms based in Tampa, Florida, known in part for their Super Shorty 12GA Any Other Weapon (AOW), is set to release an upper receiver group for the AR-15. But it’s not your typical AR upper – the SU-15 uses an operating rod and main spring, eliminating the need for a buffer and buffer tube. Hello folding stocks!

The SU-15 utilizes a fixed-piston gas system which promises cleaner, more reliable operation. Also, the upper is compatible with all standard AR lowers and uses the same bolts, firing pins, cam pins, barrels and barrel extensions.


  • Receiver: 12.55″ and 14.75″
  • Caliber: 5.56 and 300BLK
  • Barrel Lengths: 7.5″ & 16″ (5.56); 9″ and 16″ (300BLK)
Serbu SU-15 @TFB

SU-15 @TFB

SU-15 @TFB

SU-15 @TFB

Although it’s not specified, it appears that the reciprocating charging handle can be switched between either side, making the upper ambidextrous. It is also not clear if the gas block is adjustable, allowing for switching between suppressed and unsuppressed fire.  The price for a complete SU-15 Upper receiver which includes the bolt assembly, buffer, and barrel assembly. The side folding stock will be available from Serbu at a later date.

Serbu SU-15 MSRP: $795 Introductory price ($200 deposit required). $1050 thereafter.

At this point you are buying a $200 non-refundable deposit to get your place in line for the SU-15 at the $795 introductory price; deliveries will start in April. Please note in your order which receiver length you’d like and what your barrel choice is. The price is for a complete SU-15 Upper Receiver which includes the bolt assembly, buffer, and barrel assembly. Note that the final product will vary slightly from the accompanying pictures.


SU-15 @TFB


SU-15 @TFB

Current availability is showing “sold out” but if you are interested in preordering a SU-15 it never hurts to ask. Count me in as being interested.




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  • Giolli Joker

    7.5″ barrel, 300 BLK, suppressor = the Honey Badger heir.

    • TennTexan

      I’ve got a 9″ SU-15 in 300blk on order. Should make for a helluva compact package with an AGP Arms side-folder.

  • Big Burd

    $795 for an upper/buffer/barrel asym/bolt carrier group… neat product but more expensive than most ar15 upper packages.

    • Hellbilly

      It’s actually not a bad price if you consider the fact that you can get a complete no-frills lower for less than $200 these days. That means you get a neat new rifle hovering around the $1000 mark if you take advantage of the introductory discount. Besides something like a Kel-Tec or a beat-up Mini-14, you’d be hard-pressed to find a 5.56/300 carbine capable of being equipped with a folding stock.

      • Hellbilly

        “Besides something like a Kel-Tec or a beat-up Mini-14, you’d be
        hard-pressed to find a 5.56/300 carbine capable of being equipped with a
        folding stock for under $1000” is what I meant to write.

        • Cal S.

          If you do a custom build on a budget and slap a Dead Foot Arms adapter/bolt then pretty sure you could do the same for about $850. That’s without having to worry about proprietary components.

          • Sunshine_Shooter

            “…without having to worry about proprietary components.” Like the DFA bolt carrier?

            Also, has anyone done any testing or reviews on it? I really want to see how it performs in the real world.

          • Cal S.

            Indeed, but I think only the tail end of the bolt is proprietary.

          • Sunshine_Shooter

            I’d just buy an extra bolt and carrier to keep with me, but I’m not overly concerned about proprietary parts sourcing like some are.

          • Cal S.

            But in a survival situation… 😉

          • Sunshine_Shooter

            Hence the extra BCG 🙂 After 2 BCGs, I’d just stash the rifle to await the return of society and use a battlefield pickup until that time.

          • Cal S.

            Lol, indeed.

      • Gambler X

        the no frills lower, plus upper plus tax stamp…..still cheaper than my DDMK18

    • DIR911911 .

      $995 , $200 deposit + $795 purchase

      • Dracon1201

        Nope, $200 is part of the $795.

        • Klaus Von Schmitto

          That’s not how I read this.

          ” $200 non-refundable deposit to get your place in line for the SU-15 at the $795 introductory price”

          I may be wrong but that sounds like 995 to me.

          • Disarmed in CA

            It’s very poorly worded. Are they selling a $200 place in line to be able to pay the 795? (=$995) Like those “penny auctions”? and ‘non-refundable deposit’ is not a real thing, that’s called either a down-payment or a fee.

          • Dracon1201

            I had one preordered. 795 total for me.

          • Klaus Von Schmitto

            Then that’s not a bad deal at all. I hope it materializes within a reasonable time.

  • Erik B

    Very B&T?

    • Anonymoose

      Kinda reminds me of an APC or CZ805 mixed with an MCX. Speaking of which, has anyone come out with an adapter to put an ACR stock on an MCX?

      • pun&gun

        Not that I’ve seen. I’m still wondering why that’s the case.
        If the MCX had a different charging handle (or at least the ability to take aftermarket AR versions) and some kind of right-hand bolt control, I’d own one already.

  • Patrick R. – Senior Writer

    Damnit. Why do they keep putting the charging handle in the wrong place?

    Over the last several decades, American shooters have become one with the AR handle, change is hard.

    • DW

      …And yet people will argue to the death that AR charging handle is the weak link of the system

      Also AK charging handle FTW

    • Alex Brown

      I’m rather a fan of left side charging ARs. This one looks SCAR-type reversible.

    • iksnilol

      Agree completely, the charging handle should be on the right side.

      Smh, western ergonomics.

      • Wow!

        Charging handle on the right side makes no sense for a right handed shooter. Your nonfiring hand is what operates the charging handle, not the firing hand. Why reach over or under the gun when you can just grab it right in front of you?

        Same thing with folding stocks. The europeans keep putting the stock so it folds in front of the ejection port, and they keep having to invent different ways to keep it from interfering with the brass. What a stupid design! Just put the stock to fold opposite of the ejection port. Unfortunately most American companies have followed the european style the last decade for who knows what reason.

        • iksnilol

          Yeah it does. Keep a rifle pointed with only your dominant hand, I can assure you you won’t be stable and will have to reaquire the target to a larger extent than if you just held the handguard with your support hand and then charged with your dominant hand.

          I am not familiar with “european stocks folding in front of the ejection port”. AKs fold to the left, Sig’s fold to the right but it goes under the ejection port and charging handle. I’ve seen some shotguns and AR adapters folding to the right. But neither blocked the ejection port as far as I’ve seen. Maybe the Choate stock for the MP5 blocks the ejection port, but the MP5 PDW stock (the one that folds to the side) goes to the left as well. As far as I know it is a non-issue and there isn’t really any specific trend in folding direction.

    • pun&gun

      I own two ARs and I hate the position of that charging handle, as it prevents the use of any kind of cheek riser. The notion of proper gun fit still hasn’t become mainstream in the rifle community, and the ubiquity of the AR-15 and its charging handle is likely to blame for that.

    • QuadGMoto

      Count me among the “not a fan” crowd for the AR’s charging handle for three reasons:

      1) It puts the handle too close to some optics, like the Browe I have.

      2) It’s too close to the face, requiring taking the gun off target or disrupting the cheek weld to run it. This also means you can’t use a cheek riser (as others have pointed out).

      3) That charging handle is a conduit to blow gas in your face, especially when running suppressed.

    • Christian Hedegaard-Schou

      Assuming you’re a right-handed shooter (you know, like the majority 90%), then you can operate the charging handle with your left hand without moving the rifle from your shoulder, keeping your eyes on the sights/target and trigger finger ready to go.

      The traditional AR does not allow for that at all.

      If anything, this is the “right” place for the charging handle and the traditional AR has it in the “wrong” place,

  • Squirreltakular

    Very neat. Hopefully the aftermarket provides an angled charging handle soon.

  • John

    Is the barrel trunnion held in place by 6 hex nuts??

    • randomswede

      Does seam a bit excessive doesn’t it?

  • Beardedrambler

    Why oh why must the charging handle move while firing.

    • Anonymoose

      So you don’t need a forward assist.

    • TennTexan

      Actually, I believe Mark changed the design so that the charging handle is non-reciprocating.

  • Bigbigpoopi

    Did he pick the name to spite Keltec’s SU-16?

    • Anonymoose


    • Giolli Joker

      Well, Serbu Upper would sound quite right…

  • Petto

    To me it looks like a Scar16 upper for Ar15 heh

    and if it works well then this might be a better option than getting Scar16

  • iksnilol

    That folding shorty in 300 BLK seems like a good laptop gat.

  • D

    Appears similar to the ZM Weapons that was briefly sold by Para Ordinance

    • iksnilol

      AY BLYIN


      • Anon

        Mercs pls goe, ak74 fine for whole game nobody need decadent capitalist mamby pamby are

        G36 you can stay though

  • Dracon1201

    DON’T DO IT.

    I preordered about 2 years ago, it’s vaporware. According to his Facebook, Serbu put it on the backburner for his other projects and still holds the preorders. We did a group buy for it, I sold my stake after I saw what was happening. We haven’t seen anything. I had a lower set up for it and everything.

    • TennTexan

      I disagree… Mark Serbu may a reputation for taking longer than expected to deliver, but he also has a reputation for always delivering. I’ve been on the waiting list for an SU-15 since the beginning, and I’m 100% confident that I will get my upper.

      • Dracon1201

        I’m glad you’re confident and willing to wait, but most of what I stated is fact. Tell us how it is when you get it, I’m looking forward to your review. If it comes to fruition and is as great as I hoped, I may still buy, but for now, noone should be willingly stepping into this situation until we see things shipping.

      • Harambe

        You make a terribly unconvincing argument.

        • TennTexan

          I couldn’t care less whether I convince you or anyone else. Like I said, I’m on the wait list for the SU-15. Been following its development since the start. Serbu is a solid dude, and at the end of the day I trust that he will provide an excellent upper.

          • Harambe

            I’m not convinced.

          • Wow!

            You guys are wimps. I preordered the SG Works bullpup stock and didn’t get it until 8 years later. You guys need to remember, you PRE-ORDERED it. You paid for it, BEFORE it was produced. You cannot expect the company to just will it out of thin air just because you got impatient. Don’t preorder things if you aren’t willing to wait.

            And I concur, Serbu is a stand-up guy working in a small shop and producing impressive products. He hasn’t let anyone down yet.

    • Shrek

      Check out Faxon Firearms’ ARAK 21. Comes in 300 and 5.56. Works with any AR15 lower and allows for a folding stock…love mine.

      • Dracon1201

        I have. Only complaints I’ve heard are the weight of the upper. How is that?

        • Shrek

          It’s marginally heavier but, what do you expect, the recoil system is in the upper not in the buffer tube. Depending on what upper you choose to compare it with you’re only talking 2 to 6 ounce. I used an ergo stock which balanced it perfectly.

  • kregano

    Yeah, unless Mark Serbu actually starts shipping the damn things, I don’t want to hear a thing about the SU-15. I followed the ARFCOM thread about these and the sheer amount of screws ups he made was astounding. I was hoping to snag one of the 16in .300 Blackout uppers for a hunting AR build, but as I followed thread on the SU-15, I realized I was better off getting a regular .300 Blackout upper instead of waiting to see if Serbu realized firing his entire staff was a bad idea.

  • guest

    1) Remove buffer and buffer spring, put them in a more rational location
    2) Remove DI system, use a conventional piston, preferrably one that is not divided into several sub-parts
    3) Remove the bolt with too many locking lugs, 2 or 3 can do just fine. At the same time remove the retarded ejector from the bolt, use an ejector mounted solidly into the receiver that kicks the casing out.
    4) Remove forward assist.
    5) ?????
    6) Profit!!! Or just buy an AK or some similar gun that does not comprise of a patchwork of fixes for the problem that is the rifle as a whole.

    • Swarf


      Ha hahaha!

  • Harry’s Holsters

    Cool design and if they ever produce them I’d be interested in one. If they could retail complete rifles for sub $1000 I think people wouldn’t be interested. People are dying for a Sub $1000 quality rifle that isn’t an AR15 or AK.

  • Harry’s Holsters

    They should machine M Lok into the upper. Might add a little cost but I don’t see a downside.

    • Sunshine_Shooter

      That would be a good addition.

  • RickH

    Who’s the girl in the pic? Is it girls in bikinis? God I hope it’s girls in bikinis……

    • TennTexan

      That’s Mark Serbu’s daughter.

  • CharlesH

    It’s a wanna be ARAK…gotcha

    • randomswede

      One might say that when you try to “fix”/”modernize” the AR-15 there’s only two possible results: you either fail or end up with an expensive (and/or heavy) AR-18 upper.

  • Gabriel

    Didn’t Rock River already make this like.. years ago?

    • TennTexan

      Similar, but not the same.

  • Disarmed in CA

    Deposits are always refundable. That’s why they are called deposits. This is a FEE or a Down-Payment.

    • Sunshine_Shooter

      Exactly. Words mean things, and when people misuse them they destroy our language.

  • iowaclass

    Can you put it on an Ares SCR?

    • randomswede

      I was just about to type “No because the SCR has a bespoke BCG.” but the only reason for that is that they need the rat tail for the recoil spring, so probably.
      It seems the SCR uses AR-15 bolts and firing pins suggesting that the hammer hits the same spot as an AR-15 lower, further suggesting that they are indeed compatible.

  • Frank Grimes

    Yeah, I’m not holding my breath.

    He has no problem making POS .50 BMG Saturday night specials with some dork from YouTube, but Serbu has a serious problem delivering the goods when it comes to releasing good stuff.

    This will be out on the same day as the Vltor Bren Ten.

    • Frank Grimes

      Also, reciprocating charging handle, they can keep it even if it is released tomorrow.

      • TennTexan

        I believe Mark revised the design to make the charging handle non-reciprocating.

    • TennTexan

      The RN-50, while it may not win any beauty contests, is about as far from a “Saturday night special” as you can get. The thread-on breach cap is substantially stronger than other designs, including Serbu’s own BFG-50 and BFG-50A. Not to mention the fact that the cost puts a .50 cal rifle within the reach of people who can’t or don’t want to drop a huge chunk of change on a rifle. Hell, my local Wal-Mart carries American Eagle .50BMG ammo now… and it’s not that expensive! In my opinion the RN-50 is an innovative product, and it’s apparently been selling like hotcakes.

      • Frank Grimes

        Nothing that caters to the Walmart rollback discount crowd is worth owning.

        • TennTexan

          And you’re entitled to your opinion. I personally think a quality (thought admittedly bare-bones) .50BMG rifle that can be had for $1200 is a very good thing.

          Nevertheless, the RN-50 is a solid, safe rifle… Not a “Saturday night special” or some cobbled-together POS that will explode in your face.

          • Frank Grimes

            If you can’t afford a quality .50 BMG, you can’t afford a scope suitable for a .50 BMG anyway. So buying some kind of Hesse/Blackthorne/Guy from YouTube .50 BMG and pretending it’s a decent rifle, is like putting one of those spring loaded $20 bumpfire stocks on an AR15 and pretending it’s a factory select-fire M4.

          • TennTexan

            Or, to look at it another way, if you spend $1200 on the rifle instead of, say, $8000 on something like a Barrett, you’ll have plenty of money to spend on good glass.

            You obviously don’t like the rifle, and that’s fine. I see it as a great way for people to dabble in .50BMG without spending an arm and a leg.

          • Frank Grimes

            That’s like “dabbling” in Ferraris by buying a 1987 Corvette with a bodykit.

  • RaptorBob

    Make it in 7.62×39 and I’ll be interested, then I can have my own piston-operated, side-charging AK in an AR body, so I can use one of the dozen or so lowers I have lying around.

    • TennTexan

      It’s compatible with standard AR barrels and bolts. No reason why it couldn’t be built in 7.62×39.

  • Garmanarnar

    Hahaha. Read the arfcom thread before you throw money into this pit.

  • SD

    Serbu may deliver eventually, but this whole situation is an example of completely terrible business practices.

    He ran out of money to pursue the upper, even with preorders, so he’s been pumping out crappy projects to raise some more capital.

    • Wow!

      That is the risk the consumer takes with preordering, or, buying a product that doesn’t yet exist. No fault of Serbu, fault of the buyers who don’t think about how they are spending their money.

  • jim

    Headline reads: “Bufferless…”
    Twice in the article says: “The price is for a complete SU-15 Upper Receiver which includes the bolt assembly, BUFFER, and barrel assembly.”

    Which is it?

    • TennTexan

      The article is poorly worded. The SU-15 is “bufferless” in the sense that it does not use a traditional AR-15 receiver extension and recoil buffer assembly. The recoil assembly is very similar to that of an AK, and is fully contained within the upper. There are a handful of videos on YouTube that show Mark Serbu demonstrating the design.

  • jonp

    I’m wondering why I need one of these for this price?

  • Mazryonh

    This reminds me of the LR-300 AR-15-style rifle made by ZM Weapons that could use a folding stock, so this isn’t a new innovation to my knowledge.