Master Of Arms Nyx Bolt Carrier Group

Recoil management for faster follow-up shots is an elusive beast. The balance between weight savings, mechanical complexity and cost is challenge for rifle designers and shooters alike. Master Of Arms has developed the Nyx bolt carrier group to use reciprocating mass to reduce felt recoil while still being able to save weight.

I’m not going to delve into a beginner’s physics class, mostly because the commenters would have a field day with my attempt, but by lightening the BCG, moving mass is reduced along with felt recoil. The tungsten ball and spring combination (called the Dead Blow Cage) can be adjusted with additional mass to tune the rifle for specific loads and other variables like gas management. In essence, the tungsten ball moves before after the rest of the carrier, delaying the unlocking sequence and dissipating energy.

All technological advances come with a cost, be it monetary or mechanical – the complete Nyx bolt carrier group comes in at a $525 MSRP. But if it works as stated, there’s not much else on the market like it. And when it comes to competitive shooting, every advantage is a welcome blessing.


Master Of Arms Nyx Titanium Carrier:

  • Made from Solution Heat Treated and Aged, Grade 5 Titanium
    Ti 6Al-4v STA
  • All machining done post heat treat to insure no warping or dimensional instability
  • Ionbond’s Diamond Like Carbon Coating insures a long service life
  • NIB Key attached with quality Belleville washers, no staking required
  • NIB Cam-pin is less lubricant sensitive than alternatives
  • Completed with American Made Components
  • Bolt is 9310 with NIB coating
  • Extractor is Manganese Phosphate Coated for maximum friction on the case rim
  • Dead Blow Cage at the back of the carrier holds wave springs and weights for a tuned recoil experience and increased reliability.
  • 3.98oz Carrier + Key
  • 6.10oz BCG
  • 8.25oz BCG + Tungsten weight & springs
  • Made In America


Something wicked this way comes 😈 and you saw it here first #masterofarms #masteredinamerica #thenyx #smartbcg …..w options

A post shared by Master of Arms USA (@master.of.arms) on


LE – Science – OSINT.
On a mission to make all of my guns as quiet as possible.
Twitter: @gunboxready
Instagram: @tfb_pete


  • Rick O’Shay

    Geez that’s a price point.

    I guess if you’re a competitive shooter and you’re convinced this is what’ll give you the edge over your competitors, there’s no ceiling to the amount of money you’ll spend to get ahead.

  • andrey kireev

    Y Tho ? for $525 I could buy an entire rifle……

    • Youngun

      As I have already made the point, you can get a whole rifle for that price. You can also get 3 honda’s for the price of one BMW M3. You can get serveral Casio’s for the price of one Rolex. You can get a a few Delica’s for the price of one ZT 450. This is not to claim that this system is of the quality of any of these brands per se, but more to point out how obsessed with price comparison the gun world is. If people don’t buy this product because it is too expensive, it will die and you won’t have to see it anymore. If it turns out that it is effective at its stated purpose, competitors will flood the market and the price will drop. No need to cast ballots before we can see it in action. Let it come to market, and then see how it performs and make your decision with your own money and good judgment.

  • Trevor

    “In essence, the tungsten ball moves before the rest of the carrier, delaying the unlocking sequence and dissipating energy.”

    I think this statement might not be correct. There is no mechanism on a normal AR-15 that would exert force directly on a ball inside the rear of the BCG, it can only do so by moving the entire BCG first. The movement of the ball would lag behind it due to being buffered by springs on either end.

    If anything the unlocking sequence will be hastened, due to the initial mass the gas system must move being less.

    • TechnoTriticale

      Concur. My Eyeball Engineering™ suggest effects of:
      • reducing unlock time
      • leaving total cycle time relatively unchanged
      • perhaps adding some FBA effect on relock

      MoA’s product page really needs some narrative on this, if not an animation or some high speed video.

      And on the “reduce felt recoil” benefit in the article here (which may not be MoA’s claim; they just say “tuned recoil”) – I’ve never thought that ARs in .223/5.56 had any appreciable recoil, and the muzzle brakes often favored by competition shooters drive even that to nil.

      If I were to invent an improved BCG, I’d be tempted to focus on constraining the entire system to inside the upper, so that a jam OOB doesn’t prevent the upper from being opened without having to first remove the forward pivot screw (the FBA can’t always clear this, and I’ve had to unjam 2 early ARs that didn’t have FBAs).

      • Big Daddy

        I have a 18″ FN rifle length gas system on an AR with a BCM Gunfighter muzzle device. It shoots like a 22. On shorter barrels there is a lot more recoil, especially under 12″. A 7.5 or 8.5 is a lot of recoil when using a KX3/5 and is very loud. Using a brake on a barrel that short is just not a good idea, the blast and flash are ridiculous. One reason my AR pistols are either 7.62×39 or 6.8mm SPC now and I have dumped any 5.56mm under 14.5. This looks good but another proprietary and expensive piece is something I don’t need ammo for some of my guns is expensive enough. Maybe this is good for a competition gun but I don’t do that.

        • valorius

          I agree. On a 20″ AR recoil is almost non existent. The shorter you go from there, the more it increases. A 7.5″ AR pistol has quite a lot of recoil.

      • Some Guy

        My slightly educated opinion is that by buffering some of the mass of the carrier with springs you increase the duration over which the force of the mass hitting it’s rearmost point and thus reducing the recoil impulse (same force over more time doesn’t hit as hard)

        I’ll agree however that this is some silly 3-gun gamer crap and that I’d rather have an AIM surplus bolt carrier and $425 worth of hookers and blow.

        • aka_mythos

          Just to add to what you’re saying. This spring suspended mass is effectively a damper, tuned mass damper. Principally the rear spring inside the BCG is going to have a lower spring constant than the buffer spring, thus when the rifle is fired by the time the BCG begins moving rearward that gold nugget mass will already be compressing that rear spring inside the BCG. Just like other firearm concepts that delay the rearward travel of the bolt face away from the breach, the initial peak impulse here is reduced over an extended duration. Like wise as the buffer spring reaches full compression, this would level off that secondary impulse. Then when the BCG returns to a fully closed position, being a spring system there is going to some bounce back from the bolt contacting the breach. That too should be mitigated by this; where a “closed” breach will occur fractions of second sooner. This whole thing is operating on a level where its strategically shaving and adding milliseconds.

          There is something to the concept and I think its the sort of design principle a firearm designer could put to good use to create a whole new delayed blowback like firearm, but I don’t think its worthwhile here.

        • Matt Taylor

          $425… so an hour of fun and an 8 ball is more valuable than this doohickey… *duly noted*


    • Seth Hill

      I think they are using the weight of the tungsten to reduce the rearward movement through the spring (to absorb some of the felt recoil) and the forward movement through the other spring (to absorb some of the slamming shut) of the BCG, as the weight of the tungsten and the use of the springs would delay its rearward movement upon the initial movement of the BCG and it would still be moving backwards due to momentum when the BCG starts to move forward.

    • raz-0

      Well it being lightened, although not by all that much once you shove the tungsten balls in it, would shorten the time to unlock if you did not reduce the supply of gas driving the BCG.

      To do that you would use the usual methods of an adjustable gas block, or simply start with a smaller gas port.

      What this in theory would do is reduce carrier bounce when returning to battery. Which is something exacerbated by a lightened carrier.

      That being said, playing in the 3 gun world, I don’t see a lot of lightened BCG, reduced gas setups bouncing out of battery and causing malfunctions, so…

      It’s a hell of a premium to fix a not really huge problem. Maybe somewhere there’s someone trying to fix the reduced gas, light carrier, carrier bounce problem for full auto. In which case, it’s not exactly priced high for the audience.

  • Zapp Brannigan

    “In essence, the tungsten ball moves before the rest of the carrier…”

    If the ball is being held in place by a spring on either end, the ball should remain stationary for a moment, the bolt carrier moving first. The bolt carrier will start moving rearward, compressing the spring between it and the ball, then the ball will start moving backwards with the bolt carrier due to action of the spring being compressed.

    If recoil is a problem in an AR, the simplest solution is to add weight.

    • aka_mythos

      This is a competition component where weight is still an issue.

      That part of the description doesn’t make the most sense.

      I was picturing this as better controlling the rearward motion of the bcg while helping to return it to a closed position. In general this gold nugget in between springs… they have inserted a mass damper into a system that is traditionally just a spring and mass. If its done properly it should take reduce the peaks in impulse.

  • Patriot Gunner

    Or you could just develop a constant recoil system, keep the standard BCG, and retain reliability while at the same time reducing recoil. It’ll probably be a lot cheaper as well. I think inrange tv did a episode with Jim Sullivan and his constant recoil system he adapted to an m4.

  • TexianPatriot

    This industry never ceases to amaze. The Gucci products that are not needed yet still glorified astound. Tell me, why should I buy a bcg that cost so much I could make a whole new rifle. On top of that, tell me why i need help managing the recoil of a very tame system. Hell, you can manage this with a $50 compensator or brake if you actually have an AR in some unwieldy caliber.

    • Dr. Longfellow Buchenrad

      As was stated in the article, this is geared toward competition shooters who need every millisecond. Plus, you can only shoot one rifle at a time anyway. If you already have enough guns, make the ones you have better.

      And what is wrong with those who have too much money spending it on guns? If you have too much money, in order to spend it all, youve got to spend it on something you dont need. May as well be this. You cant tell me you dont buy anything unnecessary.

      And you cant blame the companies. If I knew of something people would pay tons of money for, regardless of how useless it was, you bet your @&$ Id be cranking them out.

      • Jared Vynn

        This is largely snake oil, there are plenty of products that accomplish the same claimed effect of mitigating recoil that have been tested and proven.

        An adjustable gas block combined with a low mass BCG with something like a JP captured spring buffer or a taccom 3g spring recoil buffer system (you can preload the buffer spring with it) can achieve recoil mitigation at a fraction of the cost.

        • CS

          Kynshot effectively achieves the same thing for $100.

          However, I’m wondering what the effect would be if you took this NYX bolt inconjuntion with a Kynshot and a Flatwire Spring.

          • Jared Vynn

            I have a feeling it would mostly reduce the rate of fire and change how the recoil feels, drawing out the recoil over a longer period. It could also add some forward recoil as the bcg slams forward.

          • cs

          • LGonDISQUS

            I still wanna try the Tubbs FW spring. ♡

          • CS

            Tubbs Flatwire Spring with a Spikes powdered tungsten buffer would certainly be an interesting combo.

          • cs

          • CS

        • CS
      • TexianPatriot

        I can definitely agree with you on your last paragraph. But my comment stands, I did not tell anyone what to do or buy or how to do it. Just expressed that this industry always seems to find a way to part fools with their money. More power to them. Like I said, there are already cheaper products to reduce and almost eliminate recoil. This BCG does the same thing at more than 5 times the price. It doesn’t make the gun faster. The cyclic rate really can’t be increased beyond a certain point. The magazine can’t keep up.

        • M.M.D.C.

          “…industry always seems to find a way to part fools with their money.”

          It’s the American way, dammit.

          Seriously, I need to do a little more of that myself.

    • LGonDISQUS

      2-4″ larger barrel (18-20″) does wonder’s for AR recoil too!

  • Raptor Fred

    Has your recoil experience been tuned recently? Get ready for magic, with our solid gold balls.

  • QuadGMoto

    … is an allusive beast.

    To what are you alluding? That TFB needs better proofreading or an editor? They seem to be rather elusive around here.

    • RogUinta

      I regret that I have but one upvote to give to this post.

    • Pete – TFB Writer

      Sadly, I’ve made that mistake twice in two weeks.

      • QuadGMoto

        MS Word has a grammar check that ought to be able to catch such errors for you if you’re willing to do your writing there, then paste the result into the blog article.

        • Pete – TFB Writer

          Most of my writing is done mobile. But your point is more than valid and I’m working on it.

          Seriously, I do appreciate the feedback.

          • DanGoodShot

            Watch toes dear gammer nazis!!

          • QuadGMoto

            You’re welcome. 😎

          • Core

            Don’t beat yourself up over it. I’m a scientist, and I make mistakes, and my damn mobile automatically “corrects” many of my correctly spelled words. Many words I use are not in the standard English dictionary as they are specific to geographic science other fields. Rather than go through the hassle of paying for additional dictionaries and incorporate them into my input app, I deal with it. In your case they do have some pretty cool mobile grammar apps. Try GrammarPal for android, it allows you to check for errors with a floating button. You hit the button it shows errors or potential errors, and you fix the errors and hit the button and it updates your original text. Think of it as a compartmentalized grammar editing app.

    • Vhyrus

      I don’t normally support grammar Nazis, but Trump IS president now.

      • Wow!

        Not sure if making fun of liberals calling Trump a Nazi, or is a liberal calling Trump a Nazi…

  • Dr. Longfellow Buchenrad

    Why so much negativity? Its expensive, but its cool. Let people who can afford it buy it. Dont be butthurt because you cant. I cant afford it and probably never will, but If I could, Id get one and put it in a rifle if nothing else just to see how well it works.

    • Jared Vynn

      The price is one of the biggest detractors mainly because of it being much higher than it’s perceived value. There is already a well established market for recoil mitigation and this is a new untested/unproven product priced at twice some of the highest offerings currently on market.

      • Younggun

        Which means the market will respond. If it is overpriced, people won’t pay. If it becomes apparent that the system is actually worthwhile, the price will be justified and other manufacturers will follow suite with their competing models and the price will be dropped with the influx of competition to match demand. My biggest gripe is our obsession with “need”, sometimes there is no need, there is just want. If someone has the cash, the time, and they want to buy it I say go for it. Everyone has different allocations of money and importance. That’s what makes open markets so good at serving consumers.

    • Pete – TFB Writer

      I think my spelling errors got everyone off on the wrong foot.

      • ostiariusalpha

        We’ll have to put a trigger warning in front of all of yours and Miles’ articles from now on.

        • Jared Vynn

          “keep you booger hooks off the bang switch” for example? 😉

        • Pete – TFB Writer

          Eh, I deserve the criticism. It’s all good.

      • Dr. Longfellow Buchenrad

        Everyone still knows darn well what you were trying to say. They just havent found enough things to complain about today. As one who studied engineering, I have to admit that Englishing is hard.

        • Pete – TFB Writer

          All good. I’m better than this, damn it! Lol

  • overlander

    “NIB Key attached with quality Belleville washers, no staking required”

    Nice reading comprehension

    • Jared Vynn

      Given the history of “no X required” statements I would prefer to still have staking.

      • mazkact

        Belleville washers are great but I agree that in this situation I still would stake. I use Belleville washers on a regular basis repairing equipment in a refinery and in some applications I still stake bolt heads.

    • PK

      Self cleaning M16 ring any bells?

  • Younggun

    The firearms community seems to be unique in our ability to wholeheartedly shame products that have not even made it to market yet, all predicated upon “need” when that might not be the motivating factor. Like any market, the gun market is going to have products that you do not “need” in order to accomplish most tasks that you use a gun for but how is that any different? Do you really “need” a BMW M3 to get to work and back? You could buy 3 honda civics with that money after all. Do you really “need” a blade with S35VN or M390 steel when you could purchase several Delica 4’s in VG-10 that would serve you just fine? Do you really “need” a watch that costs $5,000 when a simple Casio will do the same job at a mere fraction of the price? Welcome to an open market people. If you don’t think this will be useful, do your own research and your own financial calculations, and then don’t purchase the thing. If it is useful or more useful than other products on the market, it will succeed and soon other companies will be making competing systems and the price will go down. If the vast majority of shooters come to the same conclusion that many of you are, they will not buy this and it will no longer have the funding to continue to be manufactured. This pervasive desire to point out “need” in the gun community is exhausting.

    • TheNotoriousIUD

      More like a pervasive desire to not get ripped off.

      • Younggun

        That’s fine but it still supports my point. If there is a new $3,000 watch coming out and you go “will it tell time better than my 100$ casio” you know that watch isn’t marketed for you. If you just want your rifle to go bang, 5.56 recoil isn’t a problem for the type of shooting you do, or if your budget doesn’t allow you to spend hand fulls of greenbacks on AR-15 internals, this is not your BCG. Spending hours online excoriating a product marketed towards other people with other incomes and other priorities is just a waste of time and makes the shooting community off putting.

        • TheNotoriousIUD

          My point is that I dont believe this does what it claims.
          If im wrong after testing then ill admit it but I dont see how this can work.

          • Jared Vynn

            And the high cost is a huge disincentive to try it out.

          • TheNotoriousIUD

            Yeah, I aint being the coal mine canary for this.

          • Younggun

            Oh make no mistake, I am not lining up to buy one of these either. I don’t compete and I don’t want to be a test dummy with my own $500. If someone will donate one I’d be happy to test but yes, I will likewise wait for it to hit the market before I even consider it and even still, at my size 5.56 has never been bothersome in terms of felt recoil for the type of shooting I engage in. My point is merely keep open minds because inviting companies to take a stab at something that hasn’t yet been tried is a good thing overall.

          • TheNotoriousIUD

            I wish them success.

            Im not a big guy and I have no issues with kick. To me thats not a priority.

          • roguetechie


            Hell, I even kinda like hearing the sproing sound in my buffer tube because it helps me time double taps and tells me whether I got a good complete cycle!

            Maybe I’m just getting old and cranky though…

          • LGonDISQUS
          • Younggun

            Sure, I admit I am skeptical to say the least. If it turns out that its an overpriced hunk of metal that adds the possibility of failure to an established platform, both of our skepticism will be justified. I just caution against immediate dismissal off hand prior to testing because like most in the community, I want innovation. 20 years from now I don’t want to be shooting the same rifles because we have snuffed out any and all competitive innovation as soon as the press release hits the internet. What incentive do we leave companies to try something outside the box?

          • TheNotoriousIUD

            Im only being skeptical because theres plenty reason to be. This sounds sketchy.
            If it works, great, ill even maybe buy one. But at this price I need proof not just claims.

        • LGonDISQUS

          I wish I could find the quote about how stingy the American gun buyer is that they’d gripe over $50, just to uknowingly accept guns with poorer finishes, etc over time.

        • Rogertc1

          I’ve a Roles however it is visible when I wear it. No one can see this $525 BCG.

    • Wow!

      If it works, it won’t matter what the peanut gallery thinks. People will buy it as per capitalism. However, with thousands of minds thinking at once in comparison to a few on a team, it is more likely that flaws will be spotted somewhere among the rabble which is important for a consumer to consider before purchasing. Reviews are best, but if reviews are not available, speculation is all that can be done.

  • TheNotoriousIUD

    Hard pass.

    AR’s dont kick anyway.

    • Jared Vynn

      Somehow I feel like it wouldn’t necessarily reduce the recoil anyways more of draw it out and possibly even add in an extra bounce as the buffer bottoms out or when the bolt closes.

      • TheNotoriousIUD

        Yeah man, I must be too stupid to understand whats supposed to be happening here.

  • Darrell

    The word you seek is “elusive”.

    • Vhyrus

      How is he ever going to find it if you don’t tell him what it is then?!

      • Jared Vynn

        Well he wasn’t​ illusive in his being allusive about how elusive it was.

  • Rob

    Looks like they ripped off the Surefire suppressor optimized bolt carrier with worse execution, added some machine operations to make it appear high speed and marketed it a new group of people.

    Hard pass

  • mazkact


  • FOC Ewe

    So its a super expensive alternative to JP’s SCS?

    When AR recoil in any caliber becomes that big of a problem, its time for a PCC or a 10/22.

    • Vitor Roma

      No. It isn’t a recoil/buffer spring. Actually pairing this BCG with the SCS would be interesting.

      • Shadow

        Won’t work. The JPCS requires a hollow BCG due to the center rod the weights/spring ride on.

      • mig1nc

        You can’t add them together because the JPSCS guide rod would have nowhere to go.

        • Vitor Roma

          Ah, I see now.

  • Anon

    Wouldn’t dwell time be reduced due to initial lighter mass, and wouldn’t the gold ball work against the buffer’s dead drop. Sounds like a potential nightmare, especially in full auto.

  • Vitor Roma

    I really like the combination of titanium with super slick finish.

  • Cal S.

    “I’ll take ‘Ways to Reduce Recoil’ for…HOLY CROW! No thanks, Alex, I’ll buy a bottle or two of Tylenol if I need it that badly for my AR.”

    $525 goes a long way in recoil pads and muzzle breaks.

    • PK

      $525 would get an inexpensive 5.56 can, including the tax stamp.

  • Henry Reed

    Aaaaand the lugs aren’t rounded. Pass.

  • valorius

    Only $75 more than an entire Ruger AR556 rifle huh?

  • Bigg Bunyon

    If this thing finds a niche I’m going to start selling flash hiders for pellet guns.

  • This is basically the same thing as the Sullivan/Surefire constant recoil bolt carrier, but with using a fancy material.

    • John

      Ferfrans DSAS

    • LGonDISQUS

      I looked this up. Would be interested in trying their BCG/Buffer combo.

      Jim Sullivan: Everyone thinks they know the reason a gun kicks. A bullet goes this way…

      SAR: …and Mr. Newton tells us that there will be an equal and opposite reaction….

      Jim Sullivan: …and it’s true you can’t violate that principle, Dan, but recoil is a measure of force times time. Let’s take a simple bolt action rifle: The force of recoil is the same force that’s driving the bullet, and it’s for the same amount of time that it takes to drive that bullet. In other words, whatever amount of time it takes to accelerate that bullet from the back of the barrel to the front, and out through the front of the barrel, that amount of time is what that same force is pushing rearward against the gun and against the guy’s shoulder. Okay, of course it kicks, but here’s the thing: that time is very short, so the force is very high. Recoil is a function of force times time. In a machine gun, let’s say it’s firing 600 shots a minute, that’s ten shots a second or one shot every one-tenth of a second. You have one-tenth of a second to deliver that force. If you’re delivering it in the one-thousandth of a second that a bolt action rifle does, you’re screwed. But if you can find a way to stretch it out, instead of a thousandth of a second, stretch that time out to a tenth of a second, that’s 100 times longer. That means the force is one one-hundredth, and it’s the force that moves you, not the time. It not only means that you can reduce that force to one one-hundredth; that’s a hell of a reduction in force. It also means it becomes a constant force, because you time it so that it fires this shot and stretches all the recoil out until exactly the time it fires the next shot. So the force is not only a very small force, it is now constant. It doesn’t hit you as a bunch of sharp impacts.

    • Jan Moszczuk

      Too bad no one knows what is currently happening with them


    While I won’t claim whether this will work or not, it is much easier to make than my ideas from a month or so ago.

    According to Jim Sullivan, we all should have a heavier (than original design) BCG no matter what.

  • CA

    I love how they cut the BC so that dirt is invited in. Can’t stand these douches who know how to CNC machine, but have no real gunsmithing competence.

    • Dan

      I don’t see it letting anymore dirt in than any other BC. The extra holes are to the rear and shouldn’t get any outside dirt in them. In any case it’s not dirt i’m concerne with.

  • John

    Ferfrans SOAR with their DSAS has this.

  • John

    Ferfrans DSAS in their SOAR has been doing something similar for a very long time.

  • DanGoodShot

    Bwahahah! 5 haha t ha tt hehe twentyheeeee 5. Ahhhhh. Wait… It’s not April 1st. That already past. Your a little late Pete!

  • mazkact

    Velvet Jones(Eddie Murphy) “How many times have you said to yourself… I would like to shoot my 5.56 AR 15 but cannot take the recoil ? “

  • mig1nc

    The number of people moaning about this product because the AR15 doesn’t have much perceived recoil is mind boggling. It’s as if they have never seen a high end competitive 3-Gun match.

    When you are shooting for a $50,000 top prize and milliseconds make the difference between the top shooters, you want every possible advantage you can get.

    • mazkact

      No doubt. If this works as advertised it would be a help to a competitive 3-gun shooter.

  • Russ Kell

    I am overwhelmed by science.

  • Core

    Okay “washers” and “no staking required” lost me on this. I’ve seen gas keys that didn’t require staking seized in ruined uppers..

  • CavScout

    Wouldn’t this decrease lock time, make extraction hotter and harder, and increase actual recoil? When the ball makes the delayed push to the rear when the main mass slams back, then while recoil is moving the gun, the bearing comes back and increases it? Two stage recoil? It’ll cause more recoil because the whole gun has already started moving rearward. A mass not moving needs a lot of extra energy to get moving.

  • DChrls

    It’s the Renault F1 mass damper put in a BCG.