How airsoft and BB gun magazines work

by Tom Gaylord
Writing as B.B. Pelletier

Today’s report is another guest blog from reader Ian McKee who writes as 45 Bravo. Today he tells us how airsoft and BB magazines work.

If you’d like to write a guest post for this blog, please email me at: blogger@pyramydair.com.

Okay — take it away 45Bravo!

Ian McKee
Writing as 45Bravo

How Airsoft and detachable BB gun magazines work

This report covers:

  • It’s a replica thing
  • Low/mid capacity
  • Most of them are very similar
  • Magazine capacities
  • High capacity
  • It’s high capacity clockwork!
  • Summary
  • Coming in the future

It’s a replica thing

A lot of replica air guns have removable magazines to replicate the look and function of the actual firearm they are copied from. 

magazine lineup
From left to right, is a real 5.56/.223 30 round magazine, a 70 round mid-capacity mag, a “20 round” mag that actually holds 150 rounds of airsoft ammo, a 300 round mag, and a 850 round “fatmag”.

Both airsoft and BB guns, use the same magazine design. The only difference being the size of the projectile being used.

As much we would hate to admit it, many of our replica BB guns were first produced as airsoft guns. A LOT more replica airsoft guns are sold, compared to the replica BB gun market, partly because of laws in many countries that have more stringent regulations on BB guns than they do on airsoft. And parents perceive that the plastic airsoft projectile is less dangerous than steel BBs.  

Low/mid capacity

Spring-powered models that have to be manually cocked for every shot, normally have a full sized magazine that holds just 15-30 of the airsoft projectiles in a single column stack, and the magazine sometimes has small metal inserts inside to give the magazine some extra weight. 

low cap mags
Here are two low-capacity airsoft magazines.

Some CO2 BB guns like the Umarex Legends PPK/S, have a small removable stick magazine and keep the CO2 inside the gun, while some designs like the Sig We The People 1911 BB pistol, and the Crosman SBR (short barreled rifle) have a removable full size magazine that holds the CO2 and the BBs together in one removable unit. 

SBR mag
The magazine for Crosman’s short-barreled rifle (SBR).

Most of them are very similar

But no matter how the airguns function, the BB feed mechanism in the magazine is the same, the projectiles are held in a channel, either single stack, or double stacked, and have a spring-driven follower that pushes the projectiles up to the feed lips, ready to be fed into the chamber when needed.

1911 magazines
Do they look similar? The one on the left is from the Sig We The People BB pistol, the other one is from an airsoft 1911 I have used for over 10 years.

1911 magazines detail
This detail shot shows the similarities much better.

Magazine capacities

Airsofters that are into military simulation games (Mil-Sim), like to use a magazine that features a similar capacity as the firearm it replicates. That way the number of their magazine exchanges  plus their load out (the number of magazines they must carry) matches their real world counterparts.

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High capacity

Some magazines for automatic electric guns (AEG) use what is called a mid-cap mag, where the channel that holds the projectiles under spring pressure is longer, and may hold 60-100 projectiles. One of the advantages of a mid-cap magazine is since the BBs are under constant spring pressure, they don’t rattle when you run.

midcap and hi-cap mags
There is a spring loaded tab at the top of each magazine to keep the BBs in place until the magazine is loaded into the gun. The mid-cap mag. is on the left.

midcap inside
The BBs are under constant spring pressure while inside the mid-capacity magazine.

The most common type of magazine for the electric guns are high capacity or “high-cap” magazines. They can hold anywhere from 150 to 1000 rounds or more, depending on the size of the reservoir that holds the projectiles before feeding them into the feed channel. 

magazine bottoms
From left to right, is a “20 round” mag that actually holds 150 rounds of airsoft ammo, a 300 round mag, and a 850 round “fatmag”.

It’s high capacity clockwork!   

The high -cap magazines have a hopper that you pour the airsoft BBs into, and normally they have a wheel on the bottom of the magazine that you wind to compress a clockwork style spring that drives the feed mechanism to feed the BBs from the hopper to the gun. 

highcap mag wheel
That toothed wheel (arrow) is wound to compress a spring that pushes the loose BBs up toward the feed lips of the magazine.

As you wind the magazine wheel on the bottom, you hear clicks that are the anti reversing mechanism that keeps the spring from unwinding.  When the magazine is fully wound, a clutch in the winding assembly causes the wheel to “slip” and you hear the clicking sound different. The magazine is fully wound at that point, and you can normally empty the contents of the magazine without winding more. 

Unlike the other magazines that may have the gas stored in them, the high-cap magazines just hold and feed the projectiles. As the gun cycles, it strips off the top projectile, feeding it into the chamber. It doesn’t matter if the gun is electrically operated, or run from compressed air, or CO2 from a remote tank.

mag wheel in magazine
The magazine wheel in the magazine.

high cap mag insides
The insides are all the same, the larger magazine shells just hold more of the projectiles.

As you can see, they all have the same basic components. The highcap magazines hold the projectiles in the open areas and feed them into the feeding channel, and then into the hopup/nozzle area of the gun, as they are fired.

hi-cap mag feeding
Here you see how the hi-cap mag. takes the loose airsoft BBs and organizes them into a feed channel. That spring you wound with the exposed wheel powers this internal mechanism.

The major downside of a high capacity magazine, if you are playing in an airsoft game, is once you start shooting, there is open space in the hopper area of the magazine, and the bbs rattle when you run. So when you run from cover to cover, you sound like you have a half empty container of Tic Tacs in your pocket.   

By these photos, you would think all airsoft guns are based on the AR-15/M4 platform, but you would be wrong. These were just the magazines I had on hand. Magazines of all capacities can be had for any replica, AK47 & AK74, FN-p90, HKMP5, FNFAL, HKG3, MP7, Thompson M1A1, M14 (ALL of these replica machine guns, and others not listed do come with the giggle switch here in America.)


If you can think it, it has probably been made into an airsoft gun, with magazines and gearboxes adapted to feed it and fire it. 

Airsoft replicas are available from a Mosin Nagant 91/30, to an electrically operated M134 multi barreled minigun!

M134 minigun
Here is a $3,840 M134 airsoft minigun!

Coming in the future

In a future article, we will cover airsoft gearbox types, and other types of airsoft power plants. 



78 thoughts on “How airsoft and BB gun magazines work”

      • B.B.,

        When I put my three “select fire” steel BB guns on full auto, I involuntarily emit this sound: “Heheheheheheheheh!” It’s the same sound the Mythbusters made whenever they blew something up. :^D .


        • I have never seen a person that didn’t have a HUGE smile on their face after shooting a fully automatic weapon of any type or caliber..

          Or make that noise..

          They are just FUN!


          • Bravo
            The full auto Air Ordinance SMG I have this time is flawless.

            That I mean it is very reliable.

            When you get ahold of a full auto gun you can’t help but love it. Heck just shooting at some dirt and see the rapid clouds of dust flying its a “blast”.

            Then turn up the rate of fire and watch how big that smile gets. 😉

            • FUN and smiles are right…the kid in FM comes out every time the BB MP-40 is pulled out and fired burst-mode only. Brings back memories of pretending to be Sgt Stryker in “Sands of Iwo Jima.” With the MP this would be more along the lines of “being” Sgt Steiner in “Cross of Iron.”

              Introducing people to airguns/airsoft with full-auto fun might be a good gateway to get “hate guns” types to make 180-degree turns in their thinking and attitude.

              • FM
                I say yes. Its worth a try.

                Just ask them if they remember shooting out there star when they was kids at the carnivals.

                I bet a lot of kids did that when they was young.

                Maybe they need a memory jogger. 🙂

              • FawltyManuel.
                I have actually seen that, When we lived in Colorado, we were camping with friends out in the sticks.
                I had brought several airsoft guns, both electric, and gas for my daughter and nephew and everyone to shoot with. And a couple of firearms.
                A friend brought his girlfriend along, she was an elementary school teacher, and hated guns.

                She saw everyone shooting the airsoft guns, rolling tin cans and asked to try it.
                I taught a short class on operation and safe gun handling, and had her rolling cans in a few minutes.

                She loved full auto, and especially the M11 gas powered sub machine gun.

                She shot every round of airsoft ammo I had brought for the weekend (over 10,000 rounds), and then started on my .22LR.

                She soon bought a .22 pistol, but it wasn’t enough.

                She wanted a M11.

                We went out to Dragonmans shooting range and museum, east of Colorado Springs one weekend.
                She shot a REAL Mac11, and other machine guns.

                She eventually applied for, and got her approval and multiple tax STAMPS, for a legal Mac11 he had, with a collapsible stock, and a suppressor.

                That became her stress relief, she would go out on the weekends, burn a few hundred rounds, and Then come home and clean..

                Not including ammo by the case, in 1 year, she spent a little over $8000, and still had a big smile on her face.

                She is a true testament to presenting things in the right context, can change people’s minds..


  1. Ian,

    Nice write-up. I think B.B. must have given you photo pointers. Your photos really help explain everything.
    How do paint ball magazines work? And what is a giggle switch?


  2. Ian,

    Thanks! I really enjoy learning and as I know next to nothing about airsoft, this is real cool. I have to admit that I am not into airsoft myself, but I am very interested in how the different types work. Your dissertations are always of great interest to me.

    Now if I could just get a M134 that would shoot Smart Shot at about 800 FPS…

      • I had picked up a Strafer MKII made by Piper in a trade around 2006/2007, if I had kept it, I would have been a major stockholder in several BB manufacturers by now.

        It was a load of fun, but at about 150 bbs per second, it had a voracious appetite…

        When a 6000 round pack of daisy bbs only last a FEW minutes, unless you recovered them, and reused them, it got expensive in a hurry.

        There are free plans to build a MKII from schedule 40 pvc on the Internet, powered by a shop air compressor, the hardest part to make is the vortex block from aluminum, that took the bbs from the hopper, and fed them into the barrel without jamming.
        But with modern 3D printing, that suddenly became a lot easier.

        I had tried to make one of the DIY models, but did not have the means to make the aluminum block, I tried other methods of bb feeding but they were not reliable as the Piper design.

        As the hopper became empty, there was a lot of air coming out, but not many bbs.

      • Michael
        If you want to sell or trade something for it I would like to work out something with you.

        I almost got one new. I didn’t. Regretted that ever since.

        But I’m serious.

        • Gunfun1,

          I remember. :^) I’ll have to thnk about it. Still also in the market for an early .177 Marauder?

          I’ll get in touch with you either way, but it might have to wait a couple days because my wife broke her wrist late last week and is having surgery on it this afternoon. She’ll get a plate for certain, but the surgeon might have to do a bone graft from her hip.

          Also, I’ll need to look at it and remind myself of what I have (any extras, etc.), and I recall having a couple pics, but I can’t seem to find them on this machine. Maybe on an old thumbdrive.


          • Michael
            Man that’s a bummer. Sorry to hear about your wife. Hope she doesn’t have to have the bone graft.

            And yes about the .177 Marauder.

            And yes about the Drodz blackbird for sure. More so than the Marauder.

            No hurry. I have the money unless something crazy goes on.

            Just let me know.

            • GF1,

              The surgery went well. She got a plate and a bone graft. I was worried about a bone graft from the hip, as harvesting the bone would be a separate wound. But the bone came from a “doner” (cadaver), so very cool.

              I still have your e-mail and will keep in touch.


    • RR,

      I am not into Airsoft either, but my boys were into the skirmishing thing when they were younger so I do have a few around the house. They have their place – I have found nothing better chasing deer off my property when they show up to eat everything I plant. You can get an acceptable AEG (complete with a giggle switch) that will make them scatter (and you giggle) for a reasonable price, and they are fun to play with that way. I don’t even need to hit them anymore (and of course it does not hurt them, having been shot by these myself) – the sound alone is enough to get them running.


  3. I know nothing about airsoft and bb guns. Which shoots with a higher fps? Can you shoot bb’s in an airsoft gun and vise vera? The round balls seem about the same size…
    Why don’t air soft manufacturers use a “belt” to load their projectiles?
    Aren’t paint ball guns the same, just with larger projectiles?


    • Yogi,
      The airsoft balls are 6mm in diameter, and the steel BB’s are 4.5mm in diameter.
      So on a co2 handgun, All that’s needed for the manufacturer to change calibers is essentially a few different parts, the follower and feed lips on the magazine, the loading nozzle, and the barrel assembly.
      I can say, that a .2gram airsoft ball weighs just 3grains.
      Where a .177 steel bb weighs 5.1grains nominally

      Have you read the articles Tom has written on the Sig Mcx, or Mpx Pellet rifles?
      Loading the magazines can be tedious.

      With the volume of fire these guns put out, it is easier and faster on the shooters part to just pour the projectiles into the magazine, and let the internal feed system que the balls into the feed system.

      Paint balls are a different animal, as they are more fragile and easier to break if handled too roughly compared to airsoft or steel bbs.

      So most paintball guns tend to be gravity fed from a hopper over the gun, or clip fed from a solid clip like the Daisy 853c or the IZH 60/61 pellet rifles.

      Velocity wise, BB would be better qualified to answer that than I am, as to which is more accurate at a given velocity, and which would be more accurate at higher velocities.

      Airsoft guns use a hopup system to put a backspin on the ball to stabilize the projectile, to make the ball fly farther and straighter, using the Magnus effect.
      (Similar to how a pro baseball pitcher controls how the ball flies by putting different spins on the ball when thrown.)

      And very few steel BB guns use the system, I don’t know if that is because the steel ball is heavier, with a smaller surface area, and may not have as great of effect on the ball with a given air density.



    • Yogi,

      Good question. Generally speaking they both shoot around the same velocity — 300-450 f.p.s. When airsoft gets up over 400 f.p.s. it gets squirrley and hard to control the balls. That’s why heavier metal airsoft balls exist.

      In the $100 PCP series we saw a velocity of 910 f.p.s with a steel BB. That is exteremely dangerous, due to ricochets! And I have seen high velocitries with smaller ball bearings in a Beeman P1 pistol.

      So, steel BBs are the speed champs.


  4. The sequence of pictures really made it easy to understand how the hi cap magazine works, 45 Bravo. Looking forward to more.

    BB, I did a video a while back that sets out my airgun design in detail that I’m submitting for the contest. I’m putting in a link to the video here, but if you also need pictures, let me know and I’ll post them this evening, assuming that the type of design qualifies for this contest. Even if it doesn’t qualify, I think it will be interesting to quite a few, and has some advantages for those looking for antidotes to boredom:
    1. Very cheap to make the gun and the ammo, and parts are easy to come by.
    2. The ammo looks funny at first glance, but performs surprisingly well not only in terms of accuracy but terminal ballistics.
    3. The ammo is frangible and does interesting things to the right kind of target
    4. Operates on very low pressure

    Here is the video link: https://www.youtube.com/watch?v=vzDD49j6j90

    • MOS
      That reminds me of the story my dad would tell about the tornado that shot a piece of straw almost all the way through a picket fence.

      Yes he dissected the piece of straw from the wood fence.

      The small diameter along with the speed made the soft straw pierce the wood from the fence.

      I like your idea. I had a few blow guns in my time. Wish you luck on winning the contest.

      I guess there will be a winner? I hope so.

  5. I’m not going to be designing an airgun for the contest – skillset is not there, but if I did, it would be inspired by Anton Chigurh’s concept, as seen in “No Country For Old Men.” Might design a trolley to make the air tank more portable. Someone perhaps wants to run with the idea, but, don’t feel pressured. 😉

      • Dear BB and Readers,

        I present for you my entry into BB’s Airgun Design Challenge. It is a single shot rubber band powered catapult gun (capable of launching BBs as well as other appropriate projectiles of your choice) built from what I had around the house.

        First, however, I would like to thank BB for having this contest. It motivated me to spend a lot of time in the shop this last week week and a half. Burning the midnight oil, as it were, solving design puzzles and trying new techniques. I am excited to show you all what I made. But first a few words about what I was trying to accomplish with my design.

        As a long time reader, but first time poster, I hope I am not “oversharing” with this long post. I put a lot of effort (>40 hours) into this project and I am hoping it is something you all might be interested in.

        BB said,”The winner would be the niftiest design that the most people could build.”

        So that the most people could build it, I wanted my design to be low risk. A project for people with limited tool use and fabrication experience. A design were if something were to go wrong during the build or with the final product, the gun would not be subject to catastrophic failure, thereby unleashing a lot of pent up energy. Perhaps other novice airgun builders would be like me and find the complexities of starting to work with high pressure air, or controlling the power of a high strength spring intimidating. The design should also favor simple parts that don’t require tight tolerances and complex machining.

        I do not wish to presume BB’s intention behind this design challenge, but I speculate it was to offer people the satisfaction of making something for themselves, and participating in a new facet of a hobby that fascinates us. It was not, I imagine, an attempt to uncover an airgun engineering savant among us. As amateur airgun designers we are unlikely to best the professional engineers working in this field. This suggests that this challenge was not about making the most refined, powerful or elegant design, but rather something that offers the individual the satisfaction of making something from scratch, the use of which would provide that other joy of man: launching projectiles. A plinker, that he or she made

        Without further ado, My plinker:

        Drawing obvious inspiration from the Sharpshooter catapult guns that BB has featured on this blog, this “airgun” is a single shot rubber band powered launcher that I believe could be made various ways with relatively few tools. I made every piece of the prototype from readily available raw materials. The only parts I didn’t make were the screws, a coil spring scavenged from a retractable pen, a small magnet, and the rubber bands. I finished the project about an hour ago, so there has only been preliminary testing. I have not tried to tweak the performance, but think it is fair to say it will not satisfy the airgun connoisseurs desire for precision long range shooting equipment -but it will hit the broad side of a barn (I have been able to repeatedly hit a can at five paces). The piece favors an artillery hold. I don’t know how lightly it likes to be held, but you better point it up if you want any distance. I would rather get hit by the pea than the pea shooter, if you catch my drift.

        The heart of the design is a cylindrical bolt in a slotted tube. The bolt is attached to the tube by means of elastic bands, which drive the bolt forward to propel the shot. The bolt face has a conical recess to accept and center the BB. The design could be made as simple or nifty as you desire. Simple: tying rubber bands to a PVC tube with a wooden dowel bolt that has another wooden dowel running perpendicular through it. The slot in the PVC could take a right angle dog leg at the rear to act as a bolt catch and rudimentary trigger. Or you could build it as I have here. What additional features and style you add to the basic premise depend on your abilities and desire for “niftiness”. Because I assumed the purpose of building ones own airgun to be the pride of ownership and satisfaction of having made something, I saw no reason not to make as many parts as I could, and spend the extra time to make it nifty

        Some of the features I incorporated:

        Figured Maple stock with checkered walnut grip panels.
        Cold blued steel main tube and bolt
        Adjustable (for sear engagement) trigger with steel sear pin (pictures upon request)
        Aluminum trigger and “sear bar” (bar under main tube)
        Magnetic bolt face to retain steel shot.
        And to help the marketing men:
        Free floating barrel
        Polished Aluminum main tube end caps (barrel shroud?)
        I think it has a Buck Rogers on the American frontier- ray gun meets Kentucky long rifle vibe.

        Thanks for checking it out. Let me know if you want more pictures.
        Now to go clean up the shop…..

        A picture is worth a thousand words:

  6. We have not heard from Vana2 lately,… as best I recall. Perhaps he is cooking up an entry? We all know his woodworking abilities. Plus,… he did get a new metal lathe awhile back. Just sayin’ ……….. 😉


      • you blow air in the balloon from the other end, and the wooden peg locks the air. the baloon stays downward. muzzle load the swab into the barrel with a single soft blow by mouth. when you squeeze the peg the balloon lines up horizontally with the barrel and releases the air gently. can knock small light targets in 5 meter range without damaging anything else in the room. this was the prototype, i didnt know we would have 2 more weeks. i will make the trigger system more efficient. goal will be staying under 5 bucks. these swabs fly by the way. my goal was something anybody can built, and something that had never been made. i have not come across a cotton swab shooting balloon powered air thingy yet. so this is my invention – kinda.

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