Do Ten Round Magazine Limits Make Technical Sense?

I’ve been pondering the assertion that legislative proposals circulating in Congress and in many State legislatures make regarding limiting the size of ammunition magazines.  The fear cited most often to justify such legislation is that a gunman gone mad could expend massive amounts of ammunition quickly, reloading over and over again spraying lead indiscriminately.  Proposals run from restricting the future sale of such devices to outright criminalization of the possession including those presently legally owned.

There is of course no disagreement that an “active shooter” attack – that’s what these incidents are called in police parlance – is an undesirable criminal situation to be sure.  They are destructive episodes that disrupt the very fabric of society leading to all manner of proposals to solve or avoid the problem in the future.   Some proposals are prudent and urgent. Others are political and outlandish.  Still others start off sounding sensible but ultimately prove to be placebos or worse, have undesirable consequences.  The great task of course is to sort things out.

It is firstly important to ask what is the likely effect of a limited capacity?  Can one say it means someone can no longer spray bullets indiscriminately?  Probably it does not.  Some therefore say that in the future firearms should be, by design, slower to reload.   Will that work? Probably no. People who carry arms for both good and bad purposes will adapt.  The argument against the notion that technical features limit lethality is a false one.   Proof of it comes from the 19^th century in the days of the percussion cap revolver, a gun that held only a limited number of shots and was slow to reload.  The solution was to carry two of them.  There’s no reason to believe it will not be the case in the 21^st century.  It’s already common practice.  Police officers carry a back up gun precisely around the notion that the fastest reload is another full firearm.  The bottom line is that regardless of the law, a determined gunman will still very likely have 30 to 50 rounds of firing capacity – remember this number -- even in the unlikely event that he or she complies fully with such laws.  And I have to ask in all honesty, what psychopath planning an attack would do so?

Ok so much for criminals.  The next question the begs asking is, “Is there is a need from more than ten rounds of magazine capacity by legitimate users of firearms defending themselves?”  We’ve all heard the assertion by Senator Diane Feinstein that a five shot .38 Special revolver is all anyone might ever need.  Is this assertion in fact valid?

There’s an adage well worth bearing in mind.  It goes along the line, “If you go to a gunfight, bring enough gun.”  To garner a technical answer to how much is enough we need to delve into the physical realities of wound trauma and marksmanship under stress. Punditry aside, a gun works no differently than a club in a fight.  The object is to inflict sufficient trauma to cause your assailant to stop the attack.  Reliably stopping an opponent with a firearm takes imparting a cumulative 400 to 500 foot-pounds of energy into the vital zone of the target.  This means hitting a truly incapacitating body part and not just something peripheral.   When training police officers, the emphasis of the training is to deliver two to three shots into the vitals, I’ll spare you the list of what constitutes vital.  This works out to at least two hits in the case of modern ammunition most commonly encountered in police use such as the 9mm +P*, .40 S&W and .45 ACP with hollow point bullets and at least three in the case of older, less capable ammunition technology* designs in these same calibers.

Some departments emphasize training in combat marksmanship to accurately accomplish the task.  Even allowing for one extra shot for good measure, at accomplished skill levels, this means an operator can apply lethal force, make an assessment, and apply a second string of lethal force if need and have an ever so small reserve of ammunition left in a 10 round magazine.  That’s a pretty thin margin that does not account for the possibility to multiple assailants or the need to immediately transition to the much more difficult headshot if the threat reveals to be wearing body armor, all are very real dangers to police and civilians alike.

Police departments have long since standardized around service pistols with 15 or more round magazines because these sidearm deigns better address the margin of performance a defensive shooting incident is likely to encompass before having to reload.  A police officer typically carries two additional magazines for a total of forty-six rounds at the ready, that’s one in the chamber and 45 more rounds in the three magazines.  Note that police officers qualified to carry lower magazine capacity side arms carry just as much ammunition.  They have more magazines on their person.  Remember that number from earlier in the article?  It’s a planning factor for combat readiness. It’s a constant figure of merit that will not change.

Let’s return to the 10 round magazines and the high premium they place on marksmanship under stress.  It is costly both in terms of dedication and budget to train all officers to such levels of marksmanship.  The reality is that not all officers are good shots.   Some police department policies account for this by training around a volume of fire approach to get to the required number of vital zone hits when applying lethal force.  The trade off is calculable.  Gross error rates – one of those military effectiveness mathematics artifacts – typically estimate that a less than perfect marksman shooting under the stress of battle will land one out of every three rounds fired in the right spot.   So if one needs to make three vital zone hits, it’ll take about nine shots.   That’s one shot shy of running out of ammo with a 10 round magazine.

Actual cases show that an officer in a panic fire situation will tend to totally empty his or her gun and keep fingering the trigger even after the slide has locked back, a phenomenon seen in massive amounts of ammunition being expended in shootings.  For these officers, their side arms are often one burst application of lethal force weapons.  Not ideal by any measure.  Usually, they miss and the two bullets that find their mark and end the gunfight comes from the more skilled cop that applied lethal force correctly.

Restricting magazine capacities below 10 rounds turns the math into an even riskier game of gunfight luck.  In Cuomo country, the future average officer's 7 round magazine will yield a 70% to 80% chance of incapacitating the target.  Like the theoretical active shooter at the beginning of the article, you better believe an officer restricted to "politically correct" survival risks will be carrying a readily accessible back up gun at least equal in firepower to their primary service pistol.   Recall the active shooter from earlier in the article.  The symmetry of need is eerily pragmatic.  I think its not unrealistic to expect that departments and citizens will adapt with a renewed interest in marksmanship and the use of higher energy loadings like the .357 Magnum and its semi-auto equivalent the .357 Sig or even seriously powerful rounds like the .41 Magnum and .44 Magnum that were being explored 50 years ago before the advent  of the "Wonder Nine" pistol in the 1970's.

So let’s look at that 5-shot .38 Special revolver assertion again.  The .38 Special cartridges deliver much less energy per round than the loads enumerated earlier in the article.  One needs to place at least three and preferably four rounds to approach the 400 ft-lb’s delivered into the vitals to end the gunfight.  It’s a far more difficult firearm to shoot accurately than a full size 15-shot service pistol; in fact, the snub nose revolver is an expert’s gun that even excellent marksmen work hard to master and maintain proficiency with.  A motivated civilian who trains reasonably will likely perform no better than a 1 good hit out of every 3 shots rate.  You might get two good hits in before the gun runs dry.  This means a person so limited probably has maybe a 50% probability of incapacitating an assailant to promptly stop a threat using a low capacity, slow to reload 5-shot .38 Special revolver.  That’s the math.  It is what it is.  No.  It is not enough gun.

The Need for Legislative Diligence

What this should tell legislators is there are technical reasons why guns have come to be configured how they are today.  These configurations are not arbitrary.  They are legitimate mission driven.  They can mean the difference between life and death for persons in need of defending themselves be they police officers or citizens.  Firearms have evolved continuously to fit the mission needs of police officers and citizens defending themselves against the same criminal threats.  Regardless of the rhetoric of politics, for handguns, their present configuration embodied in the 15 shot service pistol is what makes them a “credible threat” to potential criminals, a valuable tool for legitimate defense.

It seems to me that legislators should take more time to study and understand this complex balance.  Already we see the gun industry preparing to refuse to sell to law enforcement any tools that citizens cannot have, tools they need to be that thin blue line that augments the efforts of civilians in an America where 95% of law enforcement still happens because of voluntary compliance.  It is actually a very legitimate policy question for these manufacturers to ask what is the difference between a policeman and a civilian when it comes to their needs to resist a criminal threat.  They are acting like an NGO when they point out that the question is not just some some bargaining chip to create a separate privileged class of citizen to co-opt law enforcement to supporting a law in the same way other interest groups vie for advantaged privileges from a benevolent government.  Is a cop's life more valuable than his next door neighbors?  Is one less worthy of equal protection under the law?  How soon will it be before some zealous politician places the patrol officers in a jurisdiction in the awkward position of being under gunned?   Who will take the blame when one of their names is added to the roster of the FBI’s LEOKA* statistics?

Consequence Always Happens

So what criminal adaptation consequences might stem from changing America’s firearms so they cannot be employed efficiently in self-defense?  The most common criminal adaptation seen is a phenomenon called swarming, gangs of assailants who overwhelm the defender.  The technique is as old as conflict and the equations governing the risk-reward go back to the methods from the Age of Muscle of warfare.  Simply outnumber the capacity of the ill equipped defender to resist and you win.   In today’s America, the cost to try this is still mostly unbearably high for most criminal’s tastes because of the defensive potential of firearms.  Criminals, like all predators, follow the cardinal rule of predation.  Don’t get hurt.  They prefer victim-able prey.

We risk changing this balance inadvertently as we pursue a myopic focus on the matter of mass shooters, a group that has shown a remarkable propensity to apply the principles of predation to great effect particularly in selecting locations and moments where the risk of armed resistance is remote.  The perpetrators here seem to fit a definable set of mental instability profiles that are not insofar as I have seen the subject of urgent legislation to deal with them; that's a troubling thought of another kind.  

* The 9mm +P and +P+ ammunition is a version of the 9x19mm Parabellum round designed for use in modern pistols.  Propellant is loaded to pressures exceeding U.S. SAAMI specifications designed to protect older guns from excessive stresses.  Loaded with modern expanding bullets, these rounds perform equally with other civilian semi-automatic ammunition in common use by law enforcement when shots are placed in vital zones of a target.

* Older technology ammunition includes non-expanding ball ammunition that is much less effective at delivering incapacitating trauma even when hitting a vital area.   Geneva Convention compliant “ball” ammunition authorized for use in military side arms is of this lesser effective type.

* LEOKA stands for Law Enforcement Officers Killed or Assaulted, statistics compiled annually by the Federal Bureau of Investigation.