Here’s How Many Rounds You Actually Need In Your Carry Gun

The SIG P320 M17, chambered in 9mm, comes with 17-round magazines.


Do you want to know how many rounds you actually need in your carry gun? The correct answer is you won’t know until after the fact, I’m sad to report.

Every defensive gun use situation is different. Millions of variables to consider, everything from the distance to target, number of attackers, caliber of weapon to the expertise of the shooter, etc. etc., etc., all play a factor. Trying to prescribe a universal round count, a one-size-fits-all for every concealed carrier, is, therefore, a fool’s errand. Telling you that you need “x” number does you no good because you may only need “y” or you may actually need “z.” You won’t know until the threat is eliminated.

With that said, this week, I came across an article by a brilliant writer and 2A advocate from the Cato Institute, Matthew Larosiere, that postulated that 12 was the minimum number of rounds a novice cop should have in his sidearm to reliably put down a violent attacker.

“It’s important to consider the realities of defensive gun use, which occur hundreds of thousands, or even millions of times per year. Someone who finds their home being invaded didn’t plan the encounter,” Larosiere wrote in his article “A Defense of Assault Weapons,” published by The Orange County Register.

“Even law enforcement officers have a 39 percent probability to hit a target in a high-stress situation,” he continued. “This, combined with the fact that each hit with a handgun or intermediate cartridge has only an approximate 22 percent chance to stop the target, explains the need for larger magazines. From this, we can extrapolate that a novice law enforcement officer (likely more experienced than the average American) would need about 12 shots to reliably stop a single attacker.”

I reached out to Matt to get his sources for those percentages. Numbers were plucked from a 2015 study by the International Journal of Police Science & Management, which found hit probability for novice shooters, intermediate shooters and expert shooters at typical engagement distances (3 to 75ft). Per the study:

  • Novice Shooter: 39 percent hit probability
  • Intermediate Shooter: 48 percent hit probability
  • Expert Shooter: 49 percent hit probability

Matt then juxtaposed that info against an article debunking the myth of the single shot kill, a real-life defensive gun use encounter, and academic research published by the Journal of Thoracic and Cardiovascular Surgery, titled, “Unusually Low Mortality of Penetrating Wounds of the Chest,” to surmise that each hit only has a 22 percent chance of stopping the target.

Of course, these numbers are rough approximations and not a definitive evaluation of the subject. But let’s roll with the numbers Matt researched. Let’s assume you’re a novice shooter on par with a novice police officer (per the study) and you draw your Glock 43 with a flush-fitting magazine to stop an assailant who is about to commit a forcible felony against your wife. Are 6+1 rounds of 9mm enough?

You may think that if I fire seven rounds at least two to three rounds are going to penetrate the rapist because 2.8 is 40 percent of seven. However, you need to remember there are no guarantees that any round lands on target.  It’s a highly stressful situation. Your flight, fight, freeze (aka autonomic nervous) system is kicking in so your heart is pounding and your hands are sweating. Put another way, you have a 60 percent chance of missing the target altogether after every pull of the trigger.

But let’s say this happens during the confrontation: Round 1: miss. Round 2: miss. Round 3: hit. Round 4: miss. Round 5: miss. Round 6: hit. Round 7: miss. You did hit him twice! Nice shooting! But will that stop him?

With that first hit there is a 78 percent chance that it did not. And with that second shot, even with the compounded effect of the first shot, it’s not certain that he is stopping the assault. It’s hard to exactly quantify in a percentage because there’s no way to factor in the wounding repercussions of the first hit. A bullet to the thigh is going to affect one differently than a bullet to the brain.

We’ve all heard of stories where assailants are shot 6, 7, 8 times and keep charging, especially in cases where they’re fueled by drugs. It’s a really scary thought. I guess we can state the obvious at this point. There is a reason why law enforcement officers carry duty-sized guns with a capacity exceeding 10 rounds along with several extra mags and, in some cases, a backup gun. Because when it hits the fan there are no guarantees about capacity, save one: more is better.

Let me just add that the vast majority of DGU cases don’t involve a gun even being fired.  Simply brandishing one is enough to send a perp running in most instances.  I’ve also heard people cite stats suggesting that in DGU cases where shots are fired, four to two is about the average depending on the study.  There is probably truth to that as well because the loud report of the firearm is enough of a situation resolver, to say nothing of the lead heading the perp’s way.  Presumably, most bad guys flee after hearing the first “bang.”  Most is the operative word as not all bad guys will bolt. 

Which raises the question: Does your carry loadout cover you for both types of bad guys: the common runner and the rare fighter?  I’m guessing your J-frame-sized wheel gun or subcompact carry pistol with a flush mag holds either 5 or 7 rounds, respectively.  Sure, that will work on a weak-kneed runner.  But are you confident enough that it will put down a violent fighter?

One-in-six gun owners have used a gun to defend themselves, according to Pew Research. Defending oneself with a firearm is way more common than the mainstream media lets on. But that’s a conversation for a different day. (Photo: Pew Research)

About the author: S.H. Blannelberry is the News Editor of GunsAmerica.

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  • Sheep Dog March 19, 2021, 8:09 am

    For one, training (pass/fail shooting) standards for PO, State Police are too low. I shoot 25% better than State Police standards and I do not classify myself as an expert. I have experienced the adrenaline dump more than once. Again, LEO shooting standards are…..too low.

  • Bob May 4, 2020, 7:33 am

    Here, in the US, there have been many cases where a defensive shooter was carrying more rounds than what the uniformed police carry, he shot in self-defense, and he was later charged with homicide because according to the judge he was being aggressive or in an offensive mode and looking for trouble. It was no longer a setup for self-defense but he was the aggressor since he carried so many bullets.

  • Todd Jaffe April 24, 2020, 8:06 am

    My bedside guns are a Beretta M9A3, suppressed so I can still hear if there are others, with 15 rounds of +P hollow points. If I have to fall back I have a 6 round 12 ga AR

  • Jarrod July 24, 2019, 1:55 pm

    I think the most important thing is to have a mindset of killer be killed. If you are being shot at your gun is to get out of the situation or to get to an offensive long gun. How many drive around with a shotgun or rifle in your trunk. How many have a bag with an ar pistol in it. 10 rounds should be enough to get to a defensive position to reload and make your way go next defensive position which should be an escape. The average citizen isn’t a duty sworn officer or military personnel. We just want to get home to our families. Sofa rambos will never have enough ammunition.

  • Sepp W May 25, 2019, 8:31 pm

    If I carry a pistol, 3 mags; revolver, 3 speed loaders. If I can’t get it done with that, then I’m SOL. On the road, I carry a couple of boxes of whatever I have with me.

  • Jim Cargill May 17, 2019, 10:21 pm

    Sir, thank you for your service. The reason it seemed like things went into slow mo is that you are highly trained, and fully conditioned to respond WITHOUT NEEDING TO THINK. The same is not true for probably 95% of defensive handgun owners, and PO.

    I was a combat infantryman in VN, In the 6 months leading up to that, and the final 3 months of training, in particular, I developed an “auto- response” mindset. The only thing I saw in a “first-to-fire”scenario was “friendly or non-friendly”, followed by immediate appropriate action, with zero thought. Saved my life on more than one occasion.

    I bring this up because the training we both shared was intense beyond what any civilian OR cop receives, and which would also not be appropriate for either.

  • Thomas Morrow May 11, 2019, 8:38 am

    I carry a revolver so 6 rounds has always been what I had . As a civilian the .38 special had been a constant companion. Never felt under gunned. I carried a Colt Detective special with semi wadcutter 158.

  • Joe May 10, 2019, 9:02 pm

    Hmm how did so many cavalry troopers and westerners kill each other with 38 Cal 6 shooters…. Such a mystery….

  • Karl May 10, 2019, 8:46 pm

    I have attended 4 defensive shooting classes each a week in length the classes instructors were all ex-law enforcement or military. The primary focuses were to BE AWARE OF YOUR SURROUNDINGS! If you have to use deadly force 2 shots to thoracic look for movement then on shot to the ocular! Always be aware and able!

  • Christopher Sourp May 10, 2019, 8:12 pm

    Seeing that I’m not a spare magazine carrier, my number of carry rounds depends on the magazine capacity of my EDC. Some are 10, some are more. My round count is dictated by which firearm I am carrying and the capacity of the magazine for that firearm. I load them full.

  • Dave May 10, 2019, 7:16 pm

    I had a scare a few years ago (pre-cellphone): I heard someone in my house very early in the morning. My wife and kids were gone visiting family in another state and wouldn’t be back for several days, so I knew it wasn’t one of them. I decided I didn’t need to confront the intruder, since I had no one but myself to protect and a confrontation would only be necessary if the intruder came into my bedroom searching for non-existent valuables. I was a reasonably accurate shot with my 9mm Browning BDM, but I couldn’t remember if I had a round in the chamber or not. I racked the action and ejected a round. I was now down to a measly 15 shots. I trained the sights on my open bedroom door and realized that I was shaking so badly, despite my best effort to remind myself that I had solid cover if not the element of surprise, that if the intruder was committed, it would take the entire magazine to get a possible hit.

    I waited about 20 minutes and didn’t hear any additional noise. I swept the house using my theoretical/book knowledge, only to discover whomever had been there was gone and nothing was missing. I suspect, the sound of the pistol alerted the intruder that he wasn’t alone and I wasn’t asleep, but I will never know for sure. I DO know that without specific TRAINING, I was making it up as I went along. Book knowledge doesn’t replace physical training by any stretch, and with fear, adrenaline and uncertainty, no number of bullets would have been enough!

    I have since gotten a lot more than book training and feel much better prepared. NOT looking for opportunities to verify the efficacy of my training.

    Just my two cents.

  • Sara Russo May 10, 2019, 6:18 pm

    I would love to say that I could do that well if I had to under a stressful situation. I hope that I could, I have trained myself I keep my subcompact 9mil within arms reach. But I can only hope that when a stressful situation occurs that my brain doesn’t go bye bye as many do even though it has been trained.

  • Erik May 10, 2019, 5:45 pm

    I believe that the correlation between police and civilian use of side arms is overrated, and that civilians would not be better served to prepare as the police do. Police shootings are typically from a greater distance and are often more from an offensive stance. Civilians are not typically expecting to need their gun, are usually surprised by their attacker and are almost always in a defensive stance. I think practicing at 75 ft for a civilian (if practicing for a defensive use) is unimportant. Firing at an attacker from 75 ft would probably land a civilian in jail in most states.

  • GB May 10, 2019, 4:35 pm

    I’ve gathered all my personal knowledge, training, and reviews of shootings and have come up with these
    observations. Just to clarify…My son is a LE officer, and I have been trained at a Police Academy and a pirvate LE school for a month, with all subject areas taught by acive duty LE officers. I’ve worked armed, etc.
    NO 2 shootings are alike. Perps are not alike. No set “of rules” apply to every shooting. For the record…1 shot kills do happen…IF you know what you are doing and are skilled. But, true, watching TV and movies all those 1 shot kills we see are just nonsense…for the most part. My son was forced to take a life….either him or the bad guy, at fairly close range. His first shot out of 4 was center mass with a .40 cal and the autoposy
    showed the heart was destroyed. He died instantly. He was out of the fight immediately.
    I was taught by many different LE officers that they always teach to take head shots if close enough. Some teach the occipital lobe and some teach through the mouth. Both are meant to take out the nervous system. This is taught in conjunction with the “normal” center mass shot.
    The “mouth shot” as told, accesses the top of the spinal column and thus more quickly ends the fight. When these types of shots are explained and taught to “non LE folks” you can instantly see the eyes roll and the fact they don’t seem to be “comfortable” with taking such a shot. How “comfortable” would they be lying on the ground no longer breathing? It was said earlier here….you MUST know that you can pull the trigger IF necessary. But, here’s the rub….even LE officers don’t “truly know” they can at the exact moment needed. Some die due to hesitation. Except for SWAT units, etc, most LE officers do NOT get that much experience firing their duty weapons. Some take it upon themselves to try and be as welll trained as possible, like my son has done for years. Incredible shot with any handgun, rifle and shotgun. I know, I’ve seen what he can do. I thought I was a great shot….LOL! Then you bring in the aspect of “being in the moment.” The adrenline etc, brought in to the mix makes it harder IF you are a great “pistol person” to make that shot you need to to end the fight.
    I can’t imagine a person with a carry license not carrying extra ammo on thier person. I was always taught to carry at minimum 1 extra mag…if using a semi auto. Or speed strips if carrying a wheel gun. Not JUST for extra ammo, but, in case of a “problem” requiring you to drop a mag and insert your spare.
    I know…there is much more involved….caliber, type of bullet used, etc, but, I’ve used my time here for now.

    • Dornan Lynn May 13, 2019, 12:45 am

      Am a retired Police Officer and a Combat Marine and in the number of small arms fire fights I have been involved in that in the mix of the shoot outs everything appears to go into slow motion. Shots don’t seem to be rushed and I have time to place my shots where I want. In reality everything is happening very fast. From what I have read this is not an uncommon feeling when the brain thinks you are in danger.

      • Don August 25, 2021, 8:30 pm

        Exactly. Unlike those comments regarding adrenalin that causes shaking and blurred vision etc., its my experience that adrenaline causes time to slow and focus and acuity to increase dramatically all while providing a Zen like calm.
        These other reactions are perplexing.
        Also, if you find yourself in a firefight alone with only a handgun you’re probably going down
        Occasional point, VN. On the job training only.

  • iJack May 10, 2019, 4:31 pm

    My EDC is a Walther PPQ M1. I carry it with a 17-round mag installed and 1 in the pipe, plus two 15-round mags at my 10 o’clock. I figure if I cannot get out of a confrontation jam with 48 rounds, it’s my own fault.

  • John May 10, 2019, 12:51 pm

    Rockford, Illinois, sometime around 1992. Police called to a local Kmart to arrest a detained shoplifter. During the Police interview, the shoplifter produced a handgun. Police responded and a firefight broke out.

    Police fired a total of 39 rounds, hitting the perp 6 times… point blank range!

    These were trained Police officers. So how many rounds do you need? As many as you can carry!

  • Clarence Smith May 10, 2019, 12:44 pm

    For the old NMSP officers that retired prior to 1987, they carried both issue and personal revolvers in various calibers. The sergeant (and later captain) carried an issued Colt New Service in 45 Colt, with 12 rounds in cartridge loops on his Sam Browne. Dad carried his own Pre-Model 29 (his preferred) or either an issue Model 27 or 28, all with the same belt slide set-up. Dad primarily also shot and carried handloads.

    A different time to be sure, but I know of only two times Dad removed his revolver on-duty.

    The point being is that these were imposing men, with known proficiency with firearms, that would not hesitate to use them.

    There is also another aspect to these officers, one that is noticeably absent with officers of today; they interacted with the public. They formed friendships with the public. They were approachable. They would introduce themselves to the isolated ranchers and keep in contact with them. They did this to help them do their job.

    I think it is this last aspect that has been lost in police work of today and has made a difficult job even more so.

    • Allen May 11, 2019, 5:04 am

      It was called Community Oriented Policing. I know I am likely preaching to the choir, but it was common sense, you knew the people you served. Got out of the car went and talked to people. Knew the bad guys and the good. Interacted with both. If you had a problem de-esculated confrontations when possible but used the amount of force necessary to survive and win,

  • KennethAmerica May 10, 2019, 12:23 pm

    Does anyone believe that a “rapist” (Blannelberry’s hypothetical perp) would continue his assault after being shot twice ??

    Just asking….

  • Brandon May 10, 2019, 11:59 am

    The notion that comes are at all proficient in shooting their sidearms is not accurate. The avg patrolman qualifies annually and they don’t particularly like going to the range and practicing. Then you have stats being taken from NYC where they are required to have 12 lb trigger springs. That’s why you get an avg of 12 rounds for them.

  • jay May 10, 2019, 10:45 am

    There is a logical reason for the percentage of misses, no matter the situation. It’s called the psychological factor. We as humans do not want to be put in a situation that we have to kill another human, it goes against the normal psyche. So training for a self defense situation doesn’t just involve being able to hit your target, it requires a mental attitude of, it’s me or them and convincing yourself in making that split second decision because it literally can be just that! Train your brain!

    • Bill May 10, 2019, 1:03 pm

      As a retired police officer I agree. I have always told groups that you have to have the mindset that you will shoot. Otherwise you shouldn’t carry a weapon because of the possibility that it will be used against you.

  • Kimberpross May 10, 2019, 10:43 am

    In the old west I read that gun fighters understood the 10 sec. rule. That is, even with a center mass fatal hit an assailant or other shooter will remain conscious and capable of pulling the trigger for 10 sec. before the bleed out, hence the purpose of continue to shoot until the threat is neutralized.

    As for a what I believe as a true representation of a high stress scenario, I like the movie “Open Range” with Costner and Duvall. The gun fight begins with Costner (An experienced killer) wisely placing a close range bullet in the forehead of the major threat and after that it all breaks loose with a whole lot of shooting an not much hitting.

  • Tim May 10, 2019, 10:40 am

    I am a retired cop and retired military. Back when I started in police work we were issued a 38 cal revolver and 18 rounds of ammo. Six in the gun and 12 in a dump pouch. Many of us carried extra ammo in our pockets and/or a back up. When I carried a 1911 for police work in plain clothes I typically carried two spare mags with extra ammo and mags in the car. If I had a gut feeling things could go sideways I carried five mags. In my pocket.

  • CJ May 10, 2019, 8:40 am

    Interesting article. I’m not a police officer & didn’t serve in the military either. Just a responsible armed citizen. I train & get as much info as possible. Anywhere. Books, videos, magazines, etc. I feel capacity is the way to go. Not saying I don’t carry a small revolver on occasion. Two mags, at least, depending on size of mag. I think most regular people I know in the same circles really don’t want to commit to carrying even a spare mag. Foolish.

  • Jay G. May 10, 2019, 8:27 am

    Here’s a cop who carries 145 rounds of ammo and why:

    Very compelling and food for thought!

    • EM May 12, 2019, 4:22 am

      I read about that a few years ago. The article said the criminal was not high on any drugs, which surprised the people who examined him. He was high on pure adrenaline and hate was the conclusion.

  • Big John May 10, 2019, 8:26 am

    “From this, we can extrapolate that a novice law enforcement officer would need about 12 shots to reliably stop a single attacker”…”the average for a citizen is 1.41 shots”


  • Gerald Brickwood May 10, 2019, 8:20 am

    At the end of an encounter, it is much better to be standing on your feet with unexpended ammunition left in your magazine than on your back, with a sucking chest wound because you didn’t have enough ammo!

  • Paul May 10, 2019, 8:01 am

    My 1911 I carry two backups and more nearby (in the truck or office). Plastic (9MM) one, 10mm XDM 15 rounds NONE, most of the time.

  • Lon May 10, 2019, 7:51 am

    Just like your CCW, carry the most you can dress around. Odds are, you won’t need any of it. Better to have it and not need it…..

  • BR549 May 10, 2019, 7:50 am

    The article stated, “Even law enforcement officers have a 39 percent probability to hit a target in a high-stress situation.”

    I recall a case maybe a decade ago where 7 NYPD officers fired 39 bullets at some guy in Times Square. Not one bullet hit the bad guy, and my question is this: ……… exactly where did those 39 bullets land?

    • iJack May 10, 2019, 4:21 pm

      “… exactly where did those 39 bullets land?”

      Well, there were actually THREE of these events; two in 2012 and another in 2013. I believe in the one in Times Square you are referring to, a woman pushing a walker was hit in the hip, and another woman was hit in the buttocks. The perp wasn’t hit at all.

      In the more infamous one, known locally as ‘The Empire State Building Shooting,’ nine civilians were hit by bullets, ricochets, and bullet fragments. Subsequent ballistics tests determined that all nine victims were injured by NYPD rounds,

      Sorry, but I can not remember the details of the third Manhattan shooting.

  • Frank S. May 10, 2019, 7:40 am

    It all depends on how determined an attacker is, and how much they are willing to risk death or fatal injury. A typical burglar will flee at the sight/sound of a gun. I would think a rapist would as well, unless you’re blocking the only exit. Given a chance most attackers will flee rather than face death/injury/being caught. That said, you’re less likely to stop someone who is determined to attack no matter what. So the first rule is LEAVE THE ATTACKER AN ESCAPE ROUTE. Sure, you’d like to stop them, or at least slow them enough that they get caught, but at what risk to yourself? By leaving a way out you reduce your own risk. Block the only exit and you leave them no choice but to give up or press a determined attack, and yourself no choice but to kill. While many will say “so what’s your point… in my house, that’s what I intend to do”, that may not be the best nor safest approach. While I think anyone who breaks into my house is a fool and will be dealt with, I don’t want to die or get seriously hurt, or allow my loved ones to do either, in the process of essentially exacting revenge.

  • Robert Klene May 10, 2019, 7:33 am

    I am a retired police officer. We would tell a joke. The judge asked the police officer ” Why did you shoot the suspect 15 times ? The officer answered ” Because I ran out of bullets”. One is enough if you hit the right spot, 100 in not enough if you don’t hit the right spot.

    • Dave-retired cop May 11, 2019, 5:54 pm

      Amen to that! Well said. If you put the first round where it is supposed to go,you don,t have to worry about lugging round a bunch of extra mags.

    • Ron May 24, 2019, 6:31 am

      Semi auto pistols were invented for people who miss a lot. lol Just kidding guys and gals.

  • Dr. Strangelove May 10, 2019, 6:56 am

    I’ve read that over 90% of confrontations end with the presentation of a firearm, and generally, most end after one shot. Another article that I read recently said that the average for a citizen is 1.41 shots. But in this day of spree shooters, terrorists and drug fueled criminals, can you carry too much ammo? I usually carry an extra mag.

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