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I know what you’re thinking. “Why would Magpul come out with a 40 round magazine?” It doesn’t make a whole lot of sense to make such a fuss over 10 extra rounds.  And while it may seem like nothing more than a gigantic middle finger to “high capacity” magazine banners, in reality this PMAG 40 is something that competition shooters have been lusting after for years . . .

3-gun shooting involves firing magazine-fed carbines very, very fast. And when it comes to carbines, 30 rounds is the standard magazine capacity. Whether you’re shooting an AR-15, a SCAR or some AK variant, chances are the standard magazine that comes with your gun holds no more than 30 rounds.


That standard limit of 30 rounds is something that match directors count on when they design their stages. If every competitor has a maximum of 30 rounds, then by requiring them to shoot 32 rounds they can force people to perform a reload before moving on. This adds precious seconds to their time, and introduces something else that can go wrong in the middle of a stage. In short, it sucks and the pro shooters do everything in their power to avoid having to reload.


The most obvious way  to increase your magazine capacity was to add a “coupler” to the magazine. A number of companies make devices that take 30-round Magpul magazines and turn them into 48-round monstrosities. But these couplers add a failure point to the magazine in the form of additional stress on the body of the mag, meaning that they have a tendency to break. Hence the electrical tape on Kay Miculek’s magazine, above.


The other option is Surefire’s 60- or 100-round magazines, which are what the FNH USA team usually uses. This gives you a nice buffer, as you now have double the rounds of a standard magazine, but they have a tendency to jam at the most inopportune moments. My Surefire 60-round magazine runs like a dream 90% of the time, but when it gets dirty things start going terribly wrong.

So, obviously, the best thing to do for competition shooters is to provide a magazine that holds over 30 rounds in a double stack configuration without any couplers or duct tape involved. And that’s exactly what Magpul has done.


The PMAG 40 looks and feels exactly like a regular 30 round PMAG, but a little longer. The only real difference between the two is that the spring’s baseplate on the 40 round magazine says “40 ROUND” on the bottom, supposedly to keep you from putting the wrong spring in the wrong magazine if you have a couple of them disassembled in front of you at the same time. It’s a nice touch, and shows that someone at Magpul was thinking through all the failure modes and making sure that the magazines were idiot proof.


In terms of how the magazines run, I put the mag through its paces in every caliber and firearm I could find. AR-15? SCAR-16S? Tavor SAR (yep, I bought one)? Works in all three, both fully loaded and when only a couple rounds are left. I even tried it with 300 AAC Blackout ammo and it ran like a dream.


What we have here is a magazine that makes all of a competition shooter’s dreams come true. It gives you enough rounds to skip the usual reloads, which should make you just that little bit faster in competitions. But it does come at a price, namely that the thing is massive. If you thought getting a gun with a regular magazine into a dump barrel was tough, this is going to be “round peg in square hole” territory. Nevertheless, when you absolutely positively need those 10 more rounds, accept no substitutes.

Specifications: Magpul PMAG 40 M3

MSRP: $19.95

Ratings (out of five)

Feel & Function * * * * *
They’re nice and grippy, and they work in my rifles. All of them.

Overall Rating * * * * *
Exactly what competition shooters have been wanting Magpul to make for years.

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    • Word. A 10, 20, 25, or 30 rounder in 6.8 that’s fits in a standard AR mag well would definitely be worthy of my business.

      Just to be safe, I’ll buy some of the 5.56 / 300 BLK 40 rounders as well.

      • I have 25 & 5 rnders for mine. 25’s just because and the 5’s for stand hunting deer.

      • I will be working with a place on a poly 6.8 mag.

        So far I hear Magpul has been unsuccessful in this venture, hence the reason only metal mags exist for this caliber.

        Hopefully we can get it panned out.

      • You’re going to be waiting a long time. Magpul can’t make it work for the standard AR-15 because their polymer gets to be too thick that it diminishes capacity and OAL. Stainless Steel mags from CPD are fantastic. High quality, just as cheap as a Pmag, and give you a max OAL of 2.295″.

        FWIW, Magpul DOES make a 6.8 mag, but it only fits the new LWRC-I SIX-8 rifle with the wider proprietary magwell. It’s the rifle that the Jordan military and Saudi Royal Guard use.

  1. This is precisely what I’ve been telling others who’ve questioned Magpul’s decision. When Magpul first announced the Pmag 40 (a couple of years ago at SHOT) they said it was designed for three gunners, because they knew that there wouldn’t be wide spread appeal for a magazine that was grossly longer than a standard 30 round magazines. Particularly when people already complained about the Pmag 30’s extra length.

    TL DR Summary – Not every product is designed to appeal to everyone. This is for gamers.

    • Hmmm. Now I haven’t done much in the way of competition shooting, and never Three Gun, but if the course designers want to force a reload, why wouldn’t they just start mandating that the shooters load no more than 30 rounds in their magazines?

  2. Round pegs aren’t that hard to get into square holes…square pegs into round holes on the other hand are a PITA.

  3. In the end, 3 gun, 1 gun, 10 guns, is nothing but a game. It has absolutely no connection with reality. It’s a game. Yes, time behind the trigger is good, but I think it’s just setting someone up to react in a real situation they way they have done in competition.

    Which might be better than nothing, but not by much. For real world combat force on force is where you should spend your time. And 40-50-90 round magazines won’t cut it when the SHTF. Run stick your rifle in a barrel in a gunfight and see how that works out for ya.

    • Wait, why would having extra rounds in your magazine during a gunfight be bad? I agree 3 gun is a silly game, not training. But saying having larger mags in a gunfight is a bad thing makes me suspect you are retarded.

      • Joseph, I didn’t see anyone claiming there was a connection between 3-gun and “real gunfighting,” nor did anyone suggest it as a training regimen. Peddle your strawman somewhere else. And out of curiosity, how do you know that “40-50-90 round magazines won’t cut it when the SHTF?” Spent a lot of time testing that theory, have you?

        swisssher, just because you disagree with him doesn’t make him retarded. Calling him one kinda makes you a jerk, though.

        • Matt in FL,

          Can I work as a volunteer on your campaign? If we can get just one common sense candidate into office, then there may be a change for the better.

      • I would like to be able to shoot prone. the 40 is too long for that. Probably why 30 is standard (heck, they used 20 rounders in Nam).

    • There’s a whole lot of 3 gun variations. I use stock departmental guns, sights, and holsters in mine. Decent training.

      And a reliable 40 round mag is definitely a bonus. All high cap (above 30 rounds) mags have some sort of size and weight penalty. Many are also costly and unreliable as well – which really makes them useless. I’ll plunk down $20 for these all day long (to replace the mags that I lost in the Pacific Ocean when my canoe overturned).

    • A competent martialist should still perform reasonably well in 3 gun or other action shooting sports. If you can’t break at least 50% you need to work on your gun handling and marksmanship.

  4. I’ve been using the 42 rounders available from ProMag for a while now and have not had any problems with them. That being said, I don’t run competition so I can’t comment on their suitability for that purpose.

    • Same. Will be great in the TAVOR since the Gen2’s stick a little. I love how MagPul calls these “safe capacity”!!!! Can’t believe Nick left that tidbit out from their press release!

      …”With the same compatibility as the 30-round GEN M3, the PMAG 40 provides 10 more rounds of capacity before requiring a reload—which could be a lifesaving difference. This new “safe capacity” offering…

  5. Ok…I’m retarded..with 4 real world shootings under my belt. Try going prone with a 40 rounder when the shit hits the fan and get back to me.

    • thats not the point of this magazine, there are plenty of other options where “going prone” and accuracy are above the 1.5 seconds that is needed to change magazines. 2 20 rounders can give some nice fire either accurately (scoped) or non-accurately (red dot and get it in the general area) and still maintain a low profile. 20rd pmags clear my pistol grip and bipod on my ar-15 pistol just fine. this mag isnt the best for everything, the external dimensions alone show that to be the case.

    • Must be retarded. You keep shooting yourself under the belt. Should have learned your lesson after the first time.

    • Yes, who did you shoot? Was it yourself as jaxd said? I don’t think that should count.

    • Joseph, there are multiple ways to assume and shoot from a modified prone position that prevent extended mag interference with the ground (hint: weapon does not have to held perfectly vertical). You ought to look into it; might be useful someday, even with a 30-shot mag.

    • Prone… you can shoot your rifle sideways or at an angle. Problem solved.

      For SHTF situations, you need to have a few spare magazines anyway, including 30rd mags.

  6. While there is nothing wrong with extended capacity magazines, they do get a bit unwieldy at some point. One has to wonder why don’t the rules for 3 gun matches simply require a magazine change if that is the intent?
    (Zero competitive experience here)

    • Eh, some do, but most like to give shooters the option to run the stage however they see fit. Plus, when an extended magazine fails mid-stage it tends to be more catastrophic than simply doing a reload, so there’s the possibility of an additional unplanned time penalty for using a crappy magazine. It’s all cost-benefit analysis.

      I do know one competition this year that has a maximum magazine dimension requirement for their divisions, basically limiting people to 30 rounds. So that’ll be interesting.

  7. You mention that you tried it with 300 Blk but didn’t mention super (115-150gr) or sub-sonic (200+gr). Was the spring able to handle 40 rounds of 220gr?

  8. Seems to me that all stage designers need to do is make the stage require 42 rounds. Stage Designers can certainly adapt faster than Magpul can come out with a new design.

    • Then the Surefire 60 round magazine will become the magazine of choice. Even if it is problematic sometimes, they will figure out ways to make it more reliable.

      Honestly I think 3 guns rules will eventually have to do either capacity limits, or implement a magazine size rules (similar to IPSC/USPSA). Because I doubt we are going to see 62 round stages that simply is too much shooting outside of the well known high round count matches. I don’t know about anyone else, but I find hose fests boring.

  9. “And while it may seem like nothing more than a gigantic middle finger to “high capacity” magazine banners…”

    Sounds like a perfectly good raison d’etre to me.

  10. Is there such an animal as a contest that requires bone stock factory guns? The skill of the shooter would be the only variable in such a match.

    • I think it has become like stock car racing. The cars aren’t even close to stock. The same is true with a lot of shooting competitions. I’m not going to complain too much because I want to try 3 gun and other shooting competitions. Plus I love to tinker with my cars and guns.

      • Personally I think if we are going to equate it to car racing it would be along the line of the various FIA car groups in Rally and Touring Car racing.

        If you are shooting a gun in one of the more limited divisions you aren’t competing against people in the divisions that have little rules. You are only competing against people of the same equipment class. Granted this are a little more murky in three guns as there are so many rule sets at the moment (USPSA, IDPA, 3 Gun Nation, and then you have the outlaw matches with their own rules).

    • With 3-gun, they try and keep it fair by using divisions. Depending on what equipment you’re using, you get sorted into a different group of competitors. “Tac optics” is the most popular, with one optic maximum on the rifle and only 1×3 inch brakes allowed. “Limited” is usually the newbie division, with no optics and much more strict rules. There are others, read more here:

    • I could not agree more.

      Clearly having more than a 30 round magazine (that works) would help those that have them.

      If I were going to get into something like that, I would like if more if the playing field was leveled. It saves money and does not allow those that have tons of money to have an advantage.

      Not that I have the money to spend on the ammo required to be any good at this stuff. Even if I did, it would be hard to find these days.

  11. I will buy 2-4 if just to add to the mags in circulation, which hopefully adds to the acid in Difi and Pelosi’s guts…

  12. I’m interested in the physical dimensions of the Magpul 40 rounders. I have two old steel 40 rounders that weigh 285 g (10 oz) and measure 9.5 inches top to bottom. For comparison these were $22 each ($31.44 in 2013 dollars adjusted for inflation) in the middle of the Clinton mag ban (’98 or ’99).

  13. While on a trip to Thailand I was gifted a HK ’93’ w/ factory 40 round mag for my stay. The mag was flawless but egressing a vehicle was a nightmare

  14. Maybe with that length we need an AR that has a horizantal magwell. Okay, probably dont need it and many may not want it but why not?

  15. Nice for competition, and a niche market. The main reason for this (I assume) is for marketing and visibility in competitor’s weapons. I may buy a couple for the range.

    I’m still hoping for 7.62×39 AR mags from Magpul. The platform gets a bad name due to the craptastic metal mags that they have to use. Well, that and few who build them polish their feed ramps. If you are reading this Magpul, please consider these for your product line.

  16. PLEASE, PLEASE, PLEASE, PLEASE, PLEASE, PLEASE, PLEASE, name it the “Schumer” or the “Feinstein 40” or something equivalent.

  17. While I don’t particularly need this, I ordered 2 of them (and had a friend do the same and transfer them to me before the July 1st deadline) here in Colorado just to give the ‘ole middle finger to Governor Hick.

  18. Can’t wait to be able to buy these. Magpul makes excellent products.

    If you have never done 3-gun events, it will benefit you to know that there usually aren’t magazine limitations. You can run a 20rd, 30rd, or 60rd mag if you choose, if the COF (Course of Fire) allows.

    Before the beginning of each stage, you can choose which magazine you want to use based on the COF, whether that is a standard 30rd mag or any of the high-cap mag offerings. In the 3-gun events I’ve participated in, we had the freedom to choose which mags to use for the rifle portion of the stage. The Pmag40 will be a good option if you choose to run it in a stage that requires more than 30rds.

  19. Soon only lawyers and politicians will be able to afford to fill a 40 rd mag, once the new ammo taxes kick in.

    • You can’t. They are sold out everywhere and most places will not allow backorder because they don’t expect to get any in. I have some steel 40s I can sell you for 10 a piece. You can also find steel 40s online for under 15 each. If you are hooked on pmag play the waiting game.

  20. I’ve been using Stoner and other steel 40 round ar mags forever in my serivce ar’s, they are actually available, affordable and work just as well. I like some magpul products and have a bunch of pmag 30s but I’m just not going to get excited about 10 more rounds in a pmag. Same with surefire mags and the 100 rounds drums. If I want to plink, play army and unload a flurry of rounds downrange I will do that with cheaper 7.62 firearms and ammo. Thankfully I’m a long-range 223 guy so mostly my current pmag 30s and steel 40s sit in my ammo cabinet. Larger mags are always fun but I’m so use to using a bobsled or a 5-10 rounders in my ar’s now they could make a 50 round pmag for 15 bucks and it wouldn’t get my little guy hard. If you are not a full auto person what’s the point? 3-gun? OK then.

  21. It’s hilarious to read how ANY topic posted on TTAG can generate a tussle in the comment section.

    Let’s see…Magpul releases a 40 round magazine, increasing the capacity of their standard 30 round mag by over 30%……

    Now, let’s argue about that. “It’s great!” “No, it’s stupid.”


  22. I absolutely love my 40rd Pmags
    I have three in sand un opened and three in use. Also have about 12 (30rd) in assortment of colors offered!
    How many is to many, id like #10; 40s
    And #20; 30s.
    15 for each me and the wife,
    Use in our Colts (6920) M4 and they are flawless thus far!!!

  23. I just picked up a PMAG Gen3 40 rounder today for use in my Microtech XM17-E4. It required a small amount of hand filing to properly fit my rifle, but i must say that I am very pleased with it thus far……..granted I’ve only used the mag once, but no reliability problems were experienced today during my first range trip using it. I believe I will be looking to acquire more of these magazines!

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