I’ve seen this question get brought up a bunch of times, but so far I’m not seeing a whole lot of people adequately answering the question. So I’ll do it now before I bust a blood vessel from sheer frustration.
Defending oneself against criminal violence is a very different phenomenon from an active shooter situation. Any review of security cam footage or dashcam footage that shows gunfights will make this abundantly clear…but just for the sake of clarity let’s look at this video:
In the video we see two attackers attempting to rob a jewelry store. One is armed with a handgun, the other with a crowbar. The intended victim was also armed, apparently with a handgun. In the thirty one seconds of video you see a firefight from beginning to end. Despite the fact that the jewelry store owner was armed and actually fired at the bad guys multiple times, they both stuck around and fought! They didn’t wet their pants and run away immediately like bad guys are rumored to do when presented with a gun, instead they hung around for as long as the robber armed with a handgun had bullets. (Also note how many times the handgun-armed robber actually pointed his gun at his accomplice in the process of trying to murder the good guy) In the video you can clearly see the robber armed with a handgun fire his revolver until it’s empty in the effort to kill his victim.
The intended victim fires his weapon at the robber…how many times is hard to tell from the video footage. It’s important to note how the robber responds to the shots fired at him. Watch his movement. Watch how the robbers duck and move and try to avoid the incoming fire using obstacles for whatever cover they will provide. This is not trained behavior, either…it’s instinctual. If you were ten feet from me and I started throwing rocks at your face, you’d instinctively begin to dodge and weave to avoid getting hit. Surprise, surprise…people do the same thing when bullets are being fired.
Facing multiple determined attackers who were moving and using cover to try and kill him, the owner of this jewelry store needed to outlast the bad guy’s ability to shoot to have a hope of surviving. If you’re the first one to run out of ammo in a gunfight against multiple armed opponents, it’s generally not good for your health. Even if the good guy here was an exceptionally good shot with clear lanes of fire, the number of documented instances of police having to shoot someone multiple times to get them to cease threatening actions is legion. In real life, bad guys do not fall down and die if they are hit once…and as you can see from the video, hitting a threat even in a tight enclosed space is not the easy task some believe it to be. I could post any one of hundreds of videos online that demonstrate these same principles or break down any one of literally thousands of lethal force incidents that have the same lessons in them. The chosen video is literally the first one I clicked on when I searched for “gunfight” and “camera” on youtube.
Now all of those statements concern a gunfight. Gunfights bear exactly zero resemblance to a slaughter of innocents. The key factor is that in your typical active shooter scenario the victims cannot shoot back. This renders capacity meaningless. The key predictor of body count in every active shooter scenario we’ve seen is how long it took for a good guy to show up with a gun. This isn’t really surprising when you think about how active shooters work.
At Virginia Tech Cho had to reload his weapon multiple times, but he still had no problem killing people because he chained the doors shut, delaying police response time. The few seconds it took for him to reload his firearm didn’t seem to provide any meaningful opportunity for his trapped victims to do anything useful to stop him. Recognizing that the bad guy is out of ammunition in the chaos of an active shooter event, closing distance on him, and then neutralizing him with bare hands is not the sort of thing most victims are capable of. If anyone doubts this, we can get some Sims guns or airsoft (Hell, buy a first person shooter, use a cheat code to limit how much ammunition your weapon has and then turn off the enemy AI and see how much of a meaningful limit that chumped mag capacity turns out to be.) and demonstrate pretty conclusively how 10 rounds versus 10+ rounds doesn’t bloody matter in limiting the capacity of a bad guy to do harm.
Neither would less than 10 rounds. There is a magnificent book titled Ordinary Men: Reserve Police Battalion 101 and the Final Solution in Poland. In this book author Chris Browning tells the tale of how a couple of hundred middle-aged reservists used bolt-action Mauser rifles to slaughter tens of thousands of Jews in horrific massacres. Their victims were unarmed and unable to provide effective resistance…and so the limited capacity of their issued weapons and the slow reload speed wasn’t a factor. They had control of the area and time to work, and so were able to generate an appalling body count.
Give someone time and control of the scene and it really doesn’t matter what they’re armed with…there’s going to be a body count. When you examine the active shooter situations that have taken place you see that shooters who had time managed to tally a fairly high body count regardless of how weak their weapon was or how much ammunition it was limited to. When you examine the active shooters who were met quickly with armed resistance, they didn’t manage anywhere near the same level of carnage even if they were armed with a superior weapon to the person who challenged them. Shortly before the horror in Connecticut a man tried to shoot up a mall in Oregon but only managed to kill two people before being challenged by a man who had a permit to carry a concealed weapon. You see the same dynamics at work in the Apalachian Law School shooting, the Paducah, Kentucky shooting, or the incident at the New Life Church in Colorado: The body count is limited by how long it takes for armed resistance (law enforcement or non-sworn citizens with guns) to materialize, not by the capacity or supposed lethality of the weapon the shooter uses.
This is not my opinion. This is not supposition. This is bare, hard, cold, objective reality.
When someone asks the inane question of why you would need more than ten rounds, educate them. The notion that a ten round mag limit would make any meaningful difference in the ability of an active shooter to accomplish their dastardly ends is fairytale fiction proven untrue by real events. The need for more than ten rounds on hand for defensive purposes, however, is clearly illustrated by any honest review of the dynamics of gunfights against criminal aggressors.
Again, that’s not my opinion…though I have a lot more training in the use of a firearm as a tool of self defense than most, combined with a lot more study on the topic than most so if it was just my opinion it would carry a bit more weight than most opinions. In the process of acquiring all that education I’ve stumbled across a few things that are just plain fact…truths that don’t require resting on my competence or reputation. This is one of them.
If you’re a good guy trying to defend yourself or innocent people from criminal violence, having more than ten rounds is extremely useful and in many circumstances can mean the difference between life and death. If you’re a murdering scumbag who isn’t facing armed resistance, it doesn’t matter how many bullets your weapon holds before a reload. All that matters if you’re a scumbag looking for a body count is how long it takes for someone to show up with the ability to shoot you.