Month: September 2018

Bullpups part 1: answers to some objections

I want to talk about bullpup carbines vs. traditional carbines, and why, in my opinion, the bullpup is slightly superior (but also why it doesn’t see wider support in the West). My basic thesis is this: while both designs have upsides and downsides, people tend to overemphasize the downsides of the bullpup, and ignore or even deny some of its strengths, which ultimately make it a (slightly) better design.

First, some background: what is a bullpup vs. traditional carbine? In a traditional carbine, the magazine and chamber are in front of the firing hand (think of an M-16), whereas in a bullpup, the magazine gets inserted behind the firing hand (for example, the Israeli Tavor, or the Australian Steyr AUG). The result is that the gun can be made about six inches shorter while keeping the same barrel length.

Stone’s Study

Throughout this article, I will be referring to a study by Stone et al., on the performance of shooters with bullpups. This is available at Here is the full information:

Biomechanical and Performance Implications of Weapon Design:
Comparison of Bullpup and Conventional Configurations
Richard T. Stone, Brandon F. Moeller, Robert R. Mayer, Bryce Rosenquist, Darin Van Ryswyk, Drew Eichorn First Published November 8, 2013

The Usual Analysis, and a Rebuttal

Usually, when people talk about bullpups, they give a list of pros and cons that looks something like the following (I’m taking this rather negative list from (in deference to this source, keep in mind that these objections were written in 2005):

PROS: the gun is slightly shorter (but, those who dislike bullpups will say this actually doesn’t matter).

CONS: everything else, including, but not limited to:

  1. Triggers are bad, because they are more complex.
  2. If the gun explodes, it’s slightly closer to your face because the chamber has been brought back six inches.
  3. Mag changes (reloads) are more difficult and slower, and less ergonomic: the magazine is harder to see, and is further away from the shooting hand which makes it harder to line the mag up without looking. ‘Magwells should either be in your dominant hand, or just in front of it; because it is far more difficult to manipulate anything dexterously that is located behind your dominant hand.’ Also, you have to move your hand further to get to the mag well, which slows the reload.
  4. The magazine being behind the firing hand makes it harder to fire the gun while prone.
  5. Charging the rifle can be more difficult.
  6. Because the brass ejects so close to the shoulder, you can’t use the gun ambidextrously, or else the brass will hit you in the face (this is one of the most common objections.
  7. Bullpups have a centre of mass that is too far to the rear. From the aforementioned blog: ‘The balance point on most bullpups is in between your hand and your shoulder when mounted, which is unnatural. We have a natural tendency to try to balance things between our hands, not between our hand and shoulder…. This balance will tend to make a bullpup tend to shift its butt under recoil, unless it is very tightly mounted to your shoulder; particularly during rapid fire. This tendency is somewhat countered by the position of your support hand so far forward on the barrel,  by the fact that the overall leverage moment of the muzzle is lower (the muzzle isn’t as far from either your shoulder, or your dominant hand), and by the fact that most bullpups have straightline recoil. A conventional rifle is balanced in between your dominant and support hands, and there are good reasons for that. A human being naturally handles things that balance in the palm, or in front of your dominant hand, better, because we naturally want to balance things between our hands.

Let’s address each of these points in turn. Then we will address why the ‘pros’ list should really be much LONGER than it usually is.

  1. Trigger complexity: Granted. It is possible to simplify the trigger workings in a traditional rifle more than in a bullpup. But once the trigger is made good enough, there’s diminishing returns, isn’t there? Bullpup triggers can be made so close to feeling as good as traditional triggers that it doesn’t really matter. And this ‘bad trigger’ problem does not stop the bullpup from actually being more ergonomic and accurate to shoot (see below).
  2. Again, granted, and this is probably the most severe issue with bullpups. Some rifles do try to deal with this, however; e.g. the Kel-Tec RDB has a specially reinforced shield to help protect the shooter. On the other hand, if the gun is kept in good condition, this is probably not going to be a major issue.
  3. Here I categorically disagree (and this is something that also applies to 5 and especially 7 as well, so I will answer all three objections here): bullpups are easier to handle than traditional rifles. See, by putting the centre of mass nearer to the shoulder, this means that the firing hand gets a much greater leverage advantage when trying to support the rifle during magazine reloads or even just while aiming. It’s much easier to hold a bullpup stable while doing a mag change, though this is less of an issue if you use the proper, safety-conscious civilian reload method of raising the barrel to sixty degrees above horizontal before reloading. If you want to reload while keeping the gun aimed, though, the bullpup makes this much easier, by giving your dominant hand so much leverage. After all, the gun forms basically a heavy lever with the shoulder as fulcrum. If the centre of mass of the lever is behind your grip, as in a bullpup, that makes it much easier to hold onto than if it is in front, as in the traditional carbine. A very short amount of practice makes it so you can reload without looking – and in fact, it’s not any harder to figure out where your hands are relative to one another when you slip the magazine in behind your main hand as when you put it in front. Nor is the mag well any further from your main hand with a good bullpup design than it is with a traditional design – it’s just behind, instead of in front. In addition, you can place your forearm right next to the mag well, which means you can press the magazine against your forearm to feel whether it is aligned correctly. This is not possible when the mag well is in front of your shooting hand. The only part of this objection that is valid is that you have to move your support hand further when doing the reloading.
    What’s more, Stone et al found that, when comparing the AR-15 and FS2000 reloading times, although the reloading time on the AR-15 style platform was faster than with the FS2000 (bullpup), there was no significant difference in reloading times. And in addition, the FS2000 has a particularly tightly-sealed mag well. It was deliberately made to form a very tight seal and keep out all dust. This means that other bullpups might be faster to reload than an FS2000. Regardless, the point is that the difference in reloading times is, at worst, marginally slower for bullpups, and this is more than compensated for by factors we will mention later.
  4. Somewhat valid, but probably not that big a deal, I would say. This is especially true if the gun is issued with a vertical foregrip that extends into a bipod. So it is an easily fixed problem.
  5. I don’t think this is true. In fact, the side-mounted charging handles on my bullpups are easier to reach than the ambidextrous AR-15 charging handle. Of course, these side-mounted charging handles are not ambidextrous, but this is not an inherent issue to the bullpup design: the Desert Tech MDR features a side-mounted charging handle on both sides. As the blog even acknowledges, this is more an issue of individual rifle design than of bullpup vs. conventional. Finally, as long as the gun locks back on an empty mag and has a bolt release for reloading, the charging handle won’t usually need to be used when reloading.
  6. This is probably the most common objection to bullpups: they can’t be switched from shoulder to shoulder, and hence, if you have to lean around cover in certain directions, you are out of luck: either you get smacked in the face by brass, or you die because you’re too exposed trying to fire from your main shoulder. Also, you can’t issue the gun to a left-hand shooter without doing massive changes to the bolt and ejection.
    The problem with this objection is that it only applies to bullpups with poorly-designed side ejection. Even with the most basic side ejection, a bullpup still CAN be fired from the other shoulder, as long as the shooter takes care not to put their face too far forward. But there are also numerous solutions to this problem, leading to truly ambidextrous solutions:
    The F2000 and Kel-Tec RFB both send empty brass out the front of the gun through an ejection tube. Granted, this may make clearing any jams a bit more complicated.
    The Tavor simply uses a brass deflector to ensure that the side ejected brass goes sideways or forward, and does not hit the shooter in the face. After-market deflectors are also available for the Steyr.
    The Kel-Tec RDB ejects the brass downards right next to the butt of the gun. Again, this might introduce extra complexity when trying to clear jams; also, as presently designed, it could use a dust cover to help keep the inner workings clean. However, this latter is something that could easily be fixed in design.
    Perhaps the best solution is the Desert Tech MDR’s approach, which ejects brass through a side port, but uses a relatively simple system to eject the brass forward along a diagonal, together with a robust yet compact brass deflector to ensure that the brass will not hit the shooter, regardless of which side the rifle is on.
    The point is, the problem of ambidexterity and support side shooting is one with many good solutions. It is not a problem that is inherent to the bullpup design. And even conventional rifles can have issues with ejected brass potentially hitting the shooter when doing support side shooting (though usually in the arm, rather than the face).
  7. To return to the ergonomics, I find that the reasoning here is somewhat specious. The idea that humans want to have the point of balance be between our hands sounds obvious, until we consider that this only really makes sense if we’re holding something parallel to our chests, while the gun is pretty much perpendicular to the chest. In that position, we actually want to have the point of balance as close to the shoulder as possible (think about how people carry heavy poles, for example). This is precisely what the bullpup offers. Such a centre of mass requires far less strength to maintain the position of the rifle, which translates, even for strong shooters, into less strain. This is backed up by the results of Stone’s study, which we will discuss in more depth below.

The upshot here: most objections to bullpups turn out to be blown out of proportion, or else entirely moot.

The True Bullpup Pro/Con List: Stone’s Study

Stone et al studied 48 shooters, with conventional and bullpup weapons. For the 556 NATO weapons, they used an M&P AR-15 copy, while the bullpup was an FN FS2000. The FS2000 is generally considered to have an unpleasant trigger for a bullpup, and to have rather difficult magazine changes. The study showed that after performing the challenges, the participants rated their abilities with a conventional rifle to be better than with bullpups.

But the numbers told a different story.

First of all, they did find that the FS2000 was slower to reload. This may be simply due to the FS2000 having a very tight mag well, and the fact that unlike most AR-15s, the FS2000 bolt does not lock back on an empty mag, nor does it have a bolt release, meaning the weapon must be charged after reloading – I am unsure, but I would assume that the M&P 15T Stone’s study used had a bolt release, since that is fairly standard on AR-15 platforms, which would alone make for a faster reload. In any case, the M&P 15T example that I looked at (technically, a picture of one online) clearly had a bolt release. However, whatever the reason for the FS2000 being slower to reload, they found that this difference was minimal and unlikely to be significant.

But that was not what was so surprising. The surprise was that these shooters, despite being more confident on the traditional rifle design, were actually better with the bullpups! They were both more accurate and more biomechanically stable. To quote from the study:

The results showed that the bullpup configuration resulted in more biomechanically stable users who, due to their increased stability, were able to shoot more accurately in an equivalent period of time. These results were in spite of the fact that the participants in the study demonstrated a preference for the conventional configuration.
Stated differently, the results show that bullpup weapons can be fired more quickly with the same overall accuracy. At 25 yards, the results of this study indicate differences of a few inches in accuracy between the weapons, given the same amount of time to fire. These few inches could easily mean the difference between a life saved and a life lost in an armed confrontation. At distances greater than 25 yards, a few inches could easily translate to a few feet.

Now let me propose a different list of pros and cons for bullpups vs. conventional rifles.

Bullpup advantages:

  1. Short overall length (OAL) for barrel length.
  2. Better ergonomics translating into more stability and accuracy.

Conventional rifle advantages:

  1. Simpler engineering and trigger design.
  2. Slightly faster reloading.
  3. Possibly slightly better when going prone.

Now, many people are going to perhaps question the second bullpup advantage listed here, but let us take things in order, starting with the conventional rifle advantages:

Trigger design/complexity:

It’s true that the conventional rifle can have a ‘nicer’ trigger. However, as stated before, this is going to be a marginal difference. And Stone’s study, with one of the most notoriously badly-triggered bullpups, shows how this difference really plays less of a role than one might think, since the bullpups proved more accurate and not significantly slower.

Faster reloads:

Yes, you can reload a traditional rifle faster. But do you need to? Sure, there are times when a faster reload is advantageous, but I cannot think of many cases where a tiny difference in reload time will be all that important, especially in a fireteam where other team members can provide cover while one member reloads. And even while alone, Stone’s results show that the bullpup can be aimed faster and more accurately. This seems like a bigger advantage than a faster reload.

Better going prone:

This seems like the main insurmountable advantage to the traditional design. However, it can be largely alleviated by using a foregrip that has extendable bipod feet or an extended monopod on the bottom (this appears to be something which the Israelis use sometimes on their X95 bullpup). And balancing a conventional rifle on its magazine like a monopod is hardly ideal either, while having the magazine used as an ersatz monopod behind the firing hand on a bullpup is still an option, albeit even less ideal.

Now the bullpup advantages:

Short OAL for a long barrel:

This is an advantage which really seems to get understated a lot, perhaps because it is to some extend situational. I have heard from a guy who was in, I believe, the Singapore military, who, if I am remembering rightly, talked about seeing trainees with conventional weapons have a much harder time in CQB (close quarter battle) training than those armed with bullpups, because it is so much easier to get a longer weapon caught on something in cramped conditions. However, it’s true that if you are just talking about shooting at a range, or even in a competition – even a competition that seeks to simulate tactical conditions, such as the two and three gun matches exhibited frequently on InRange TV (a truly excellent channel about guns, by the way – my disagreement with them on bullpups is despite the fact that Karl and Ian know far more about guns than I do) – you may not realize the advantages that having a short OAL and a long barrel provides.

The thing is, a short OAL is good for use in close combat. But you can get a short barreled rifle (SBR) in a conventional design, and it is about as short as you can make a bullpup (past 25-26 inches, there’s not much point in making the carbine shorter, since you would lose any place to put your support hand). So why not just use an SBR? For civilians in the US, the answer is simple: an SBR requires a class III stamp from the ATF, and while anyone who can pass a background check can get this, it is an extra expense and a royal pain, really. But what about for military/LE?

Well, the SBR is fine for close quarters combat. But the advantage the bullpup provides is that it gives you an SBR-sized package with a DMR (designated marksman)-sized barrel, and hence SBR size combined with DMR ballistics. In other words, you can swap from easily clearing a house or fighting in a jungle with extensive undergrowth, to taking a shot at the farthest distances a conventional battle rifle is capable of, with ease. This also means the bullpup will be putting more energy into the bullet, and hence in general will have better stopping power, even at close range. The SBR will have a lower energy bullet, and it will lack accuracy at ranges where the bullpup still operates very well.

Bullpups have better ergonomics and accuracy:

This is the point of which I think most people are simply unaware. The traditional argument usually is bullpups having good length vs. bad triggers, bad reloads, and bad ergonomics. But I think the idea that bullpups have bad ergonomics is just wrong. They actually have good ergonomics. Why, then, do people think otherwise? Well, if they’re American shooters, perhaps it is because they grew up shooting traditional rifles. Many shooters in America start with basic .22 rifles and hunting rifles, which are much closer to the traditional carbine than do a bullpup. So it is possible that they are simply used to the feel of such a rifle. After all, if we are used to doing something a certain way, then even if some other approach is better, it will still feel wrong when we do it.

What Stone et al found, of course, was simple:

American shooters think they do better with traditional carbines, but in fact they are more stable and more accurate when shooting bullpups.

I mention ‘American’ here because the participants in Stone’s study, insofar as they were trained, were more likely to be trained on traditional carbines than on bullpups – Stone’s paper acknowledges that there was a strong pro-conventional bias among his participants as a result of both national bias and bias from previous training. If this is true for American shooters, it is probably as true or more true for shooters from other nations, who are likely less biased.

This is a major plus for the bullpup, if the result replicates (and assuming the results were not obtained by some statistical sleight-of-hand). Of course, as with any study, one must be careful and make sure that the results replicate (i.e. that when we try it again, we get similar outcomes as the first time). We must also consider that sometimes it is possible to ‘hack’ the data in ways that give a desired outcome. Therefore, Stone’s results should not necessarily be taken as definitive. And in fairness, Stone’s study is fairly recent (2013 publication) and not very well known. But to my mind, this is the definitive argument in favour of the bullpup. While it does not mean the bullpup is so superior to the traditional rifle as to render the latter obsolescent in any way, it does mean that the design is likely to be more ergonomic and to give rise to higher levels of stability, and thus accuracy, in shooting, which gives the bullpup design a definitive edge.

But Militaries Aren’t Using Bullpups?

It is worth noting that the US military has never shown interest in adopting a bullpup, and that at least two nations which did adopt bullpups are moving away from them (the UK and France). However, there are a few points to be made here.

  1. France is moving away from the bullpup because the FAMAS is outdated, not because it was badly designed. And their choice of a conventional rifle in the HK 416 is more or less motivated by logistics – they no longer have the ability to domestically procure rifles, and the HK 416 is what is available. The same sort of applies to the UK, which also had a very bad experience with the L85, not because it was a bullpup, but because until HK fixed it with the A2, it was a wretched gun. The HK 416 also is a well-tested platform. The upshot is that these nations are going for tried and true, easily available weapons, and those happen to be conventional, in part perhaps because the US likes conventional weapons.
  2. The US military has often been on the wrong end of weapons advancement when it comes to small arms. They refused the high-capacity lever action rifles (e.g. the Henry) in the late 1800s. They did adopt self-loading rifles as standard in WWII before anyone else had done so, but immediately thereafter, they insisted on a full-power cartridge over an intermediate (this would prove to be a bad mistake), then insisted on the M14 over the FN FAL (another mistake). Not to mention that weapons procurement is just in general notoriously political in the US – consider the naval ship that senator Trent Lott pretty much forced the navy to build, the F-35, and the many other politically-motivated projects in which the US military is forced, or chooses, to engage.
  3. Militaries need to be concerned about things like durability and reliability, as well as resistance to dirt and the like – these are issues which are more about the particular firearm than about conventional vs. bullpup design. The M4 platform, and related platforms, are extremely reliable not because of its conventional design, but because of precision machining and the fact that over time, the design has been substantially refined. By contrast, many bullpups are relatively new designs. If the M-16 had been given a bullpup design, which would have been perfectly feasible, then perhaps we would see a bullpup with the same sort of reputation for reliability and excellence as the M4 sees today.
    In any case, apart from a marginal increase in complexity in the trigger system, bullpup design does not in itself have much effect on reliability or durability.
  4. The US is loathe to adopt foreign designs. A big part of the reason for the M14 winning over the FN FAL was because the latter was a Belgian design. The bullpup is ‘tainted’ with being an Austrian/British/French/’generally furreign’ design.
  5. Militaries like to do things the way they’ve always done them. There’s a good reason for this in part: if it isn’t broken, then trying to improve it could actually make things a lot worse. Since conventional M4s and M4 SBRs are more than adequate, then, why try to change things? Which leads to…
  6. Militaries have far better things to spend money on, than changing an infantry platform that is performing adequately. Even though I am a bullpup fan, if I were in charge of US military procurement today, I would not try to replace the M4 with a bullpup, because it would be a waste of money. Yes, we could get something slightly better in a bullpup; no, that doesn’t justify the expense, when what we have works well enough to do the job.
    I would argue, though, that the marines missed a great opportunity for a bullpup when they chose to replace the M4s with the M27 IAR. A bullpup would have provided the same marksmanship and long-range suppressive fire in 556 NATO that the M27 gives, while keeping the closer quarters battle capabilities which seem like they might be quite important for marines. But perhaps the M27 has enough parts in common with M4s that it makes more sense logistically. There might have been some unfortunate ‘real riflemen shoot conventional rifles, and every marine is a real rifleman’ sort of mentality that influenced the decision, though.
  7. Plenty of militaries, including large or ‘respected’ militaries, have adopted bullpups. For example, the Chinese, the French, the UK, the Australians, and the Israelis. And of these, only the French and the UK are rejecting them, and this is because of logistics, not because of any flaw in the design of bullpups. The other nations continue to use them, apparently quite happily.

I am, therefore, unimpressed by the fact that the US refuses to use bullpups. And when we analyse those nations which are choosing to replace their bullpups with something else, the reasons are inevitably logistical (they’re trying to update their weapons, and the major production facilities from whence they can purchase are manufacturing M4 or HK 416 derivatives) rather than based on a shortcoming of the bullpup design per se. A former British special forces operator with whom I was able to talk was greatly in favour of bullpups, for example, despite having extensive experience with many weapon platforms.


I do not believe that there is a definitive winner in the bullpup vs. conventional carbine debate, at least not if we are looking for one design to be clearly superior to the other the way that, say, a breech loader was superior to a muzzle loader. However, the evidence does suggest that at worst, the bullpup is as good as the conventional rifle, with a couple of minor weaknesses (usually overstated) and a couple of minor strengths; at best, however, the results of Stone’s study suggest that the bullpup has a major advantage in ergonomics and potentially accuracy. This is, however, not a decisive enough advantage to render the bullpup worth choosing over a conventional design when faced with either:

  1. A bad bullpup design vs. a good conventional design. While a bad breech loader was probably better than a great muzzle loader (as long as it was functional and not outright dangerous), a badly-made or designed bullpup is probably worse than a well-made, well-designed conventional rifle, since all the accuracy and ergonomics in the world will not help if the gun will not shoot.
  2. Logistical demands such as those now faced by France, which make it easier/cheaper to procure conventional rifles.