The Simple Arithmetic of High Capacity Gun Magazines

In the wake of yet another mass shooting tragedy today, let’s examine the costs and benefits of high capacity gun magazines. I previously examined the cost-benefit of private gun ownership in the US, and noted at that time that the extraordinarily negative cost-benefit ratio might eventually become an issue for the pro-gun lobby (the industry generates economy-wide economic losses of over $15B/year) [1].

High capacity magazines [2] seem to have become a feature of virtually every recent mass-shooting in the US [3]. How many lives might have been saved by eliminating high-capacity magazines? Let us conservatively assume 10 deaths per year might be reduced through this policy (a rounding error compared to the roughly 10,000 annual gun homicides in the US). The economic value of 10 lives can be estimated at $80 million, while the annual sales revenue of high-capacity magazines might be less than $20 million (since gun magazine sales are a tiny fraction of gun sales, and magazines can be had for as little as $15) [4].

Measuring tragedy on an economic basis might seem crass, but it helps establish a key point: not only are high capacity magazines empowering individuals in mass shootings – but they are also provably hurting America as a whole, as they subtract value from our nation! An outright ban on possession of high capacity magazines is thus a reasonable step to limit further damage to America’s citizens and economy.

Let me address a number of potential criticisms here:

  • Would-be mass shooters will acquire weapons and high-capacity magazines illegally, so you are only affecting law abiding citizens. Actually, 75% of weapons used in mass shootings were acquired legally, and recent shooters acquired their weapons legally. Most of these shooters had no previous criminal record, so in the event high-capacity magazines were illegal, it’s unlikely that they would even know how to find them illegally.
  • Banning high-capacity magazines would have no effect on death rates, as shooters would simply reload. In the Gabrielle Giffords shooting, the gunman was stopped in his rampage once he stopped to reload. Reducing magazine capacity to 10 rounds reduces total firing capacity – this is simple arithmetic. In both of these shootings and many other incidents, lives would have been saved. For that matter, lives might be saved in incidents like drive-by shootings where the rapid fire of multiple rounds makes victims of innocent bystanders.
  • High capacity magazines are needed for self-defense. Even the police rarely find need to fire large numbers of rounds. Is there even one documented case of self defense where the potential victim needed more than 10 rounds to deter his attackers? There are outliers in everything, but I’d be surprised to hear of such a case.
  • I have a 2nd-Amendment right to whatever capacity magazine I like. The recent Supreme Court case upholding an individual right to a firearm also upheld the right to ban American citizens’ access to fully automatic weapons, grenades, tanks, and all other manner of military weapons. Even Justice Scalia admits that there are restrictions on the 2nd Amendment. Your right to purchase whatever weapon you like has long since been curtailed, and the government retains the right to enact reasonable restrictions on access to arms.


[1] Using more recent numbers on the economic value of human life at $8M per life, the gun industry may actually cause annual economic losses in the US of $200B per year (8M * 30k lives lost – economic value of gun trade). I republished the more conservative estimate above to remain consistent with the original analysis that I referenced.

[2] I am defining high-capacity magazines as those holding more than 10 rounds, as defined in the original assault weapons ban.

[3] Limiting gun capacity would have reduced casualties in a number of recent tragedies:

[4] Gun sales are estimated to have reached an annual rate around 12 million this year. If separate high-capacity magazine sales are in the neighborhood of 10% of all gun sales, and magazines cost around $15, then total annual revenue from this business might be 1.2M * 15 = $18M. This is an imprecise estimate, since gun sales are not tracked, but conveys the order of magnitude, and illustrates the tiny economic benefit supplied by this particular product relative to its cost in human life.

23 thoughts on “The Simple Arithmetic of High Capacity Gun Magazines

  1. I believe guns in general also account for 70% of all homicides. So shouldn’t a tool that is used for the majority of all homicides be highly regulated? I am not saying banned, but intensely regulated. What is the economic benefit of a HCM? The financial derivatives markets and financial markets in general are more open to regulation (sarcasm), and they don’t kill anyone, though they can do serious damage to people’s lives.

    1. 70% of the homicides that are committed are by felons that can’t get their hands on legal firearms. If you look at statistics, violent crimes and murders all greatly increased (average of 40% increase over the greatest amount of incidents) when gun bans were placed (i.e. D.C., Florida, Michigan etc. see link When a criminal knows an entire state is disarmed, nothing stops him from commiting the crime. Magazine capacity as well (as you stated you don’t believe in banning, but regulating) high capacity magazines make hardly a difference in these mass shootings. If law abiding citizens weren’t prevented from carrying in movie theatres, malls, grocery stores, and banks, these shootings would be virually non-existent. Limiting a magazine capacity merely means the criminal must now take time to tape 2 or 3 or 4 mags together before going out for a murder-spree. For me, I’m trained to defend civilians around me including me, my family and anyone at any given time of a radical violent moment. I can reload a magazine in about 0.8 seconds in a handgun and about 2.3 seconds in a tactical rifle. So you tell me, limiting a rifle to 20 rounds instead of 60 and a handgun limited to 7 instead of 18… what difference does that 0.8 or 2.3 seconds make? NONE. Now, the victim will have 2 more seconds to run and he’ll get shot in the back instead of the chest. But for citizens, it makes a huge difference. It’s life or death. If i miss those shots I’m gone along with everyone else. Shortening/limiting the rounds in a magazine makes it so that if I am walking at night with my girlfriend and I am engaged by 4 men/women violently, I better place those 7 shots perfectly… But unfortunately that is physically impossible. I can draw from concealment from 20 yards and put 2 rounds in the thoracic cavity in 1.8 seconds. But that is target practice. In the face of combat or a real life situation, your training and accuracy falls 75% due to adrenaline and stress. So, yet again, these limitations merely make my life more difficult to defend. Sure, it may never happen. But I would rather say I were fully prepared, than say I wish I was and I wish my mother or father or brother didn’t die. These bans/regulations are ridiculous. There are millions of statistical polls and factual evidence submitted by police stations and law enforcement agencies all over the world. Also proven factually, after the age of 12, 50% of individuals will experience a violent crime in their lives. 45% will experience a successful crime, and 25% will be killed by a violent crime. Also, did you know that fatalities due to firearms make up 0.4% of all fatalities? In all reality, we should be banning cars for god’s sake. Turn your worries to something a little more important. Limiting magazines won’t do a thing but cause more deaths of good, hard-working people like your family and my family. No intent to offend. Just inform

  2. The Second Amendment says ‘The right of the people to keep and bear arms shall not be infringed’. Your information is pure garbage!

    1. No, the 2nd amendment says “A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed.” so quote the whole thing, not what is just posted on the NRA building. The post is measuring things economically. Not taking away guns, but pointing out a more common sense approach regarding what we should be keeping and bearing to help us become a safer society while still allowing ownership of a handgun.

      1. Law abiding citizens that carry ARE carrying to defend the “security of a free state.” What would you call it when a robber walks into a bank with an automatic PKM and a glock firing rounds at civilians (which, this bank of course as do all the others, has a sign on the front door saying ‘no firearms allowed…’ that clearly stopped the robber) and a citizen like myself takes him out… would you not say that that individual was protecting a free state? NRA is the only thing standing between complete gun bans for semi-automatic weapons and freedom, as intended by the founding fathers. Look up some facts man. “safer society while allowing ownership of a handgun?” FACTUAL statistics show that the more guns to law abiding citizens, the less the crime.

      2. The issue is not the type of weapon or the number of rounds that the murderer has. It is the murderer. A man went into a Chinese school and killed 20+ people with a knife. In addition, the worst school massacre in the United States was committed with dynamite. The issue is the lunatics that commit the crimes, not which weapon they use to do so.
        And just as a side note, gun laws nationwide have become dramatically less stringent over the last 15 year. As a direct result, gun murders have gone down by nearly 40% and gun crime in general has dropped by nearly 70%. This clearly blows a hole in your argument.

  3. How many magazines with capacity over 10 rounds are there in the USA? I would guess around 5 per semi-auto, given estimated 10 million semi-auto’s- = 50 million magazines. So, you are going to identify (you don’t know who has them since they are not registered) and confiscate 50,000,000 magainzes from an estimated 7 million people. Does that really sound reasonable? Would love to hear how you plan on doing that! Please put a cost estimate along (with body count) on accomplishing your theory since you seem good at that (but I bet you won’t in this case because you know what the cost will be).

    1. Mike, a logical plan would be as follows:

      1. Ban the sale and importation of new and existing high capacity magazines. This would stop the trade of new and existing high capacity magazines, but individuals would be allowed to keep existing magazines.

      2. Use buyback programs to diminish the number of high capacity magazines on the market. This is far less expensive than gun buybacks, and would over time significantly diminish the number available since new high capacity magazines would not enter the market.

  4. It’s interesting that you only account for the economic impact of lost income of those killed. What about offsetting gains in resources saved? Less water drunk or used for bathing and flushing the toilet. Less electricity used (also resulting in lower carbon footprint). Less gasoline and oil used commuting to work. Fewer other natural resources (plants and minerals) used for clothing, shelter, food, etc. If you’re only going to do a half-assed economic analysis, don’t bother doing one at all.

    While you’re at it, please do your CBA for abortion. There are approximately 850,000 abortions per year in the US, according to the latest (and more conservative) CDC estimates. If each of these prevented lives are worth $8 million, that’s $6.8 TRILLION in lost income…versus how much in lost revenue for abortion doctors? Therefore, we must outlaw abortion. After all, it’s simple arithmetic, right?

    You need to learn that rights do not amount purely to their corresponding economic terms.

    1. Bemused, population does in fact increase GDP, and so to the extent that abortion lowers population growth, it may in fact lower GDP. A counterargument there (posited by Levitt et al) is that the least-wanted fetuses are aborted, and if those children were born, they would tend to be least well-cared for, and thus become less productive or even counter-productive in society.

      Regarding your criticism of the analysis here, it’s not couched in fact. You could dispute the $8 million per human number – that would be a valid line of argument. Here, I’ll make your argument for you: If annual GDP / person in the US is roughly 50k, and a human lives roughly 80 years, then the rough value of a human life should be $4M, not 8M as other researchers have estimated. I will explore this topic in detail in another post. But even with this lower estimate, the economics don’t fall in favor of high-capacity magazines.

    2. Just realized another mistake you made…comparing apples to oranges. In accounting for the value of a human life, the $8 million figure includes trickle down benefits to the economy at large, not just the individual’s lifetime income — which according to your previous article is actually $1.4 million. That’s $14 million in lost individual income per year versus what “might be less than $20 million” in lost HCM sales revenue. That’s a heckuva lot closer in value than you are making it out to be, and may actually favor the HCM side of the equation.

      If you want to use the $8 million per person value, you are going to have to subsequently account for the associated trickle-down benefit to supporting industries of HCM manufacturers (such as suppliers, marketers, shippers, etc), not to mention the beneficiaries of those wages spent by the workers directly involved in the HCM industry, since that is also a factor in the lifetime value calculation.

      Again, not that you can actually put a value on human life…but if you’re going to do so, you need to be consistent in your analysis.

      1. Bemused, the old analysis I made is out-of-date, and I do intend to write another post with a better estimate on the value of human life. Such a value is, unfortunately, necessarily for a huge range of cost-benefit decisions, most not related to the present conversation on weapons. At any rate, I think a value of $4M is in the right ballpark today, though other researchers have constructed estimates as high at $8M, as I noted in the original post. If you do some searching, you’ll see that the government and others actually use values for human life in the range of 4-8M as well, whether at the EPA, or at a private firm estimating its own legal risks.

      2. I saw in the Times article to which you linked that FedGov agencies use wildly varying numbers, and are directed to use a value that can vary between them by as much as $9 million:

        The Office of Management and Budget told agencies in 2004 that they should pick a number between $1 million and $10 million. That guidance remains in effect, although the office has more recently warned agencies that it would be difficult to justify the use of numbers under $5 million, two administration officials said.

        It also noted the effect that politics has on the process, meaning the actual value may have absolutely no relation to reality at all.

        Regardless of all that, I have little quibble with the actual number, but rather with your methodology. You either need to compare income vs. revenue, or lifetime GDP vs. HCM GDP. Though that 2009 article of yours to which you linked in this one may be outdated, I doubt the lifetime income average has grown substantially in the past 3+ years. As it is, the rough HCM revenue number you present also appears to be little more than an educated guess. If you are going to draw this type of absolute conclusion…

        An outright ban on possession of high capacity magazines is thus a reasonable step to limit further damage to America’s citizens and economy.

        …you had better also have absolute economic numbers in hand to prove that there actually IS damage to the economy. Esoteric value on one hand versus educated guess on the other is no basis for economic fact.

      3. Bemused, I am comparing annual economic value of 10 deaths vs. annual economic value of the HCM industry. I agree with you that the estimate of the size of HCM industry is an estimate, as it’s hard to find concrete data there. But I am comparing apples-apples here – annual economic impacts in this case against each other. The annual impact of a human life termination is in essence an NPV number, and that’s how it becomes an apples to apples comparison.

      4. Yes, you are using the annual economic value of 10 deaths, which includes wages earned and subsequently spent on food, housing, etc. Total value = apples.

        But you are not using the annual economic value of the HCM industry. You are only using — as you stated in the OP — “annual sales revenue“. You are completely discounting the subsequent economic impact of that revenue as it is spent on suppliers, marketing, shipping, etc, and the additional impact of the HCM workers wages as they are also spent on food, housing, etc. Revenue only = oranges.

        Again, you either need to compare revenue to revenue, or total economic impact to total economic impact. By ignoring the fact that other industries also benefit from sales of HCM — not just the gun industry — you fail to compare them on equal grounds. Ergo, apples to oranges.

        Ask yourself this: Does the figure for the economic value of one life include spending by that person, and subsequent spending by the people who have taken in that revenue? Does the figure for the “annual sales revenue” of the HCM market similarly include spending by those HCM manufacturers, and subsequent spending by those manufacturers’ suppliers, marketers, and shippers?

        To me, those answers are “Yes” and “No”, respectively. I await explanation if you see them differently.

      5. You make the mistake here that most Chambers of Commerce and other boosters make when estimating the impact of a new factory or company on their economy. The correct way to estimate the impact of an industry, say the HCM industry, is to to estimate the total value added by that industry (in the way that a VAT is calculated) – by measuring the actual economic value added by only that industry’s sales, less the value of raw inputs. This number is necessarily lower than its total sales, not higher. So my estimate of HCM economic impact is actually a ceiling, not a floor (as I have not deducted the cost of raw materials).

        Let me put this another way. If we attempt to estimate GDP using your approach, by adding up every bit of revenue and sales up and down a value chain, we will end up with a US GDP estimate several times greater than the actual $15 trillion figure. We must count only the value added by the industry, not all the transactions up and down the chain or we will end up double-counting. Here’s a link – first page explains the issue and solutions.

        When counting the economic value produced by a net additional human being, we can estimate this simply using numbers like per capita GDP, as you have agreed.

        If I were you, I’d be quibbling with the following in my approach:

        1. What are the real sales of HCM’s in the US?
        2. Please provide a real, honest NPV analysis for your estimate of the value of an (American) life.
        3. How on Earth do you know that HCM’s are responsible for 10 deaths, or less, or more, per year?

        These are questions that deserve more research. I’m currently working on #3.

      6. You prove the point I am trying to make, in your item #2. The VSL which is used in this analysis is not that same as gross wages, which is what you must use if you are going to compare it to gross revenue of the HCM industry. Way back in your first response to me, you suggested a more valid critique might propose using GDP* rather than VSL, which is exactly what I’ve been saying all along.

        Your #1 I already addressed indirectly, and your #3 goes without saying; I went with your 10 as a hypothetical given to address the calculation.

        *Though I wouldn’t use per capita GDP, either, and certainly not for the 80 years you used, since a person is not being very productive whilst in diapers — either baby or adult. Well, productive in waste, I suppose, but not something that adds to GDP. Instead, I would use the CPS mean income over 40 years (25-64), adjusted for inflation…which is what I took the $1.4 million in your 2009 article to represent, for example. To me, your earlier example of lost income plus externalities is more correct than the VSL approach you employ here.

      7. Look for a future post on #3. As for #2 – actually levelized GDP/capita * 80 years is pretty accurate, precisely because it’s using an average. Working age people on average are producing far in excess of 50k/worker, as they are supporting those on both ends of the spectrum (well federal debt supports the seniors, but that’s another story, and still contributes to GDP). At any rate, a good discussion – I welcome well-formed dissenting opinions.

      8. Indeed, and I must apologize for initially calling your analysis “half-assed”. So many of these I run across are simply knee-jerk responses to the latest mass shooting, and reach for the most convenient numbers at hand. Your ability to back up your reasoning proves you are not one of them.

        As for one of the technical critiques of HCM magazines which you attempted to forestall in your OP:

        Banning high-capacity magazines would have no effect on death rates, as shooters would simply reload.

        Your pre-rebuttal noted the Giffords incident and how the shooter was neutralized when he stopped to reload. However, it should also be noted that the shooter dropped the magazine he was reloading, which is probably a statistical anomaly that would not factor into an analysis of shooting time vs deaths. That could have happened whether it was high-capacity or not.

        As far as anecdotal evidence goes, I would also point you to three other shootings: the Newtown , Fort Hood, and New Life Church incidents.


        “Police and other first responders arrived on scene about 20 minutes after the first calls.”

        Twenty minutes is plenty of time to reload several times with magazines of any capacity. The argument that the few seconds it might take to reload will allow potential victims to run away would not apply here, as those kids were most likely frozen with terror in the first place; it would simply not occur to them to run when there’s a break in the shooting.

        Fort Hood:

        An investigator later testified that 146 spent shell casings were recovered inside the building.[33] Another 68 casings were collected outside, for a total of 214 rounds fired by the attacker and responding police officers.[33][39] A medic who treated Hasan said his pockets were full of pistol magazines.[40] When the shooting ended, he was still carrying 177 rounds of unfired ammunition in his pockets, contained in both 20- and 30-round magazines.[33] The incident, which lasted about 10 minutes,[41] resulted in 30 people wounded, and 13 killed—12 soldiers and one civilian; 11 died at the scene, and two died later in a hospital,

        Again, ten minutes is more than enough time to reload multiple times, no matter what the magazine capacity is. What saved the lives of those civilians who were not shot was the shooter’s intentions, not the capacity of his magazines.

        Now, compare those two incidents with the New Life Church, where the shooter had over 1,000 rounds of ammunition and HCMs:

        At this point, Assam opened fire on Murray with her personally owned concealed weapon. Police say that after suffering multiple hits from Assam’s gun, Murray fatally shot himself,

        Would a law banning HCMs have resulted in only 2 victims dead and 3 wounded there? Or would it have been the presence of an armed parishoner? Which one would prove to be more effective in preventing deaths?

      9. Sorry, that last comment was not meant to further discussion along these lines here on this post. It was only something for you to consider when you are drafting your post for item #3.

        Thanks for the discussion.

  5. The “costs” you attribute to “the gun industry” are actually the costs associated with human acts involving gun industry products. Same old dirty trick, different camouflage.

  6. Your estimate on the total revenue is completely off. Magpul and ugi make that in a year off ar mags. And those are only two of the company’s that manufacture magazines. And ar’s aren’t the only firearms with “high cap mags” all full size service pistols have 12 plus rounds in the Mage based off caliber.

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