Unintentional Discharges: The Mutant Cousin Under the Basement Stairs

I would like to discuss something that, in firearms instructing circles, seems to be the metaphorical mutant cousin living under the basement stairs. It’s something that many instructors (and shooters) want to believe doesn’t exist. When it rears its ugly head every now and then, they belittle, blame and condemn, then force the little monster back into the basement and bolt the door. They dare not whisper its name lest it reappear. The hideous beast of which I speak is, of course, the unintentional discharge. OK, so maybe I’m exaggerating a little, but it has always bothered me that instructors spend so little time, relatively speaking, on such an important topic.

After several officers in our metro area experienced unintentional discharges in a short time span, I thought it would be a good topic for a continuing education class. As is usually the case, I casually consulted with other firearms instructors in the area to see what type of curriculum they had and if I could steal any of their information for my class. Surprisingly, most instructors looked perplexed when I asked them about it, like I was breaking some unwritten rule about speaking of the monster under the stairs. The most common reply was, “We tell ‘em to keep their finger off the trigger. If their finger isn’t on the trigger, the gun won’t go off.” Someone would inevitably re-enact the scene from the movie Blackhawk Down, where the Delta soldier puts his index finger up in the air and says, “This is my safety.”

safest position

Finger off trigger and along the frame is the safest position, but it is not a natural position. Under stress we seek what is natural – a closed fist.

In most cases it’s true that if you keep your finger off the trigger, the gun probably won’t fire, but we know from studying slips, conditioning, and stress responses that, despite what you may think, you are not always in control of your trigger finger. This little fact became more apparent when I found a U.S. Government review of 267 shooting incidents by agents from the FBI, ATF, DEA and U.S. Marshals Service during the period of fiscal years 2000 to 2003. According to the study, a total of 102 (38%) of those shootings were unintentional. If the nation’s brightest and most well-trained officers have such a staggering number of unintentional discharges, then it really is amazing that the rest of us aren’t dropping like flies. All kidding aside, what is apparent is that current training programs are arguably deficient in addressing the matter.

Main Causes of Unintentional Discharges

Most firearms training programs I have been through acknowledge four main causes of the unintentional discharge. They are as follows:

* Disregarding safety rules

* Postural disturbance

* Startle effect

* Maximal exertion of force/sympathetic response

The first item on the list is the blanket that covers the hindquarters of trainers and rangemasters everywhere. This is also where trainers and training programs can, in my opinion, produce the greatest impact. Enforcement of safety rules is a cognitive, empirical function that creates conditioned responses. I would posit that an examination of any unintentional discharge will point to at least one violation of the cardinal safety rules. However, as we have seen, sometimes there can be underlying and unseen causes for those violations.

postural disturbance

Postural disturbance of the worst kind. The primary safety on any firearm is muzzle direction, but keeping the finger along the frame helps prevent a UD.

A postural disturbance is essentially an abrupt loss of balance. It will cause involuntary gross motor skill actions to occur to prevent a fall/injury – one of which is a grabbing motion.

Startle means: To disturb or agitate suddenly as by surprise or alarm; to cause to start involuntarily, by or as by a sudden shock. The startle effect typically causes involuntary gross motor skill reactions similar to the postural disturbance.

In simplistic terms, the sympathetic response is basically one hand doing what the other hand does. Under stress, I grab with my left hand and my right hand will grab also. If there’s a gun in either hand, there is an increased risk of it firing.

Related Causes

In the last few years, we have added four other/related causes of unintentional discharges:

* Contralateral contractions

* Hand confusion

* Trigger reassurance

* Yips

The theory of contralateral contractions was originally credited to Dr. Roger Enoka (circa 1991) and confirmed by subsequent research. What we have come to realize is that the hand gripping a gun is affected by sympathetic reflexive reactions to the movement of not just the hands, but also that of other limbs of the body. These reactions cause uncontrollable contraction of the fingers. It is more than just one hand doing what the other hand does (as was originally thought).

unintentional discharge

Unintentional discharge by a student at the range. Arrows show bullet path.

In complex motor skill actions, a large number of muscle groups in different parts of the body necessarily work together, and they do so subconsciously. Studies have shown that jumping motions, whether with both legs or a single leg, cause the greatest contraction of the [trigger] finger. The next greatest [trigger] finger contraction was created by an abrupt loss of balance – a postural disturbance. Third was single-leg kicks, particularly with the weapon-side leg. The postural disturbance is something that happens by accident or surprise, so to minimize the risk of a UD, we practice the “finger off trigger and along the frame” position. Otherwise, if we are running, jumping or kicking, the best thing to do is holster.

Directly related to the phenomena of the sympathetic response and contralateral contractions is the concept of hand confusion. According to studies done by the Force Science Institute, if you have a firearm in one hand and a flashlight in the other, under stress you intend to activate the flashlight but your brain mistakenly sends contraction signals to both hands or to the wrong hand, resulting in an unintentional discharge. The risk increases when hands are crossed, as with the Harries flashlight/weapon technique.

flash light technique

Risk increases when hands are crossed. Harries flashlight/weapon technique. Practice reduces the risk.

FSI studies have also discovered that there is an apparent psychological need for the reassurance that is afforded by putting one’s finger on the trigger, called simply trigger reassurance. This psychological need is heightened under low-light conditions.

Last on my list is the yip. In all my years of firearms instructing, I had never heard of it until I started looking into causes of the UD. According to the Mayo Clinic, a yip is an “uncontrollable, forceful spasmodic jerk” originally observed in some golfers. It is associated with abnormally high heart rates, and some individuals appear to be more susceptible than others. It appears to be undiagnosable and for the most part cannot be explained. After thinking about it, I realized that a few times I have experienced something like a chill running through my body that caused an uncontrollable twitch of different muscle groups. Under the right circumstances, I can see how such an action might cause a trigger finger contraction, particularly if other safeguards are not in place.

UD Experiment

As an experiment into the effects of conditioning and the causes of unintentional discharges, one year I decided to change the way our department ran annual qualifications. For years we’d used turning targets for qualifications. While we did have training that incorporated movement, decision making, and no-shoot targets, our semiannual qualifications were fairly standard in that during the course of fire, when a target faced, the shooter engaged that target with a predetermined number of rounds.

neutral target

Neutral target can represent either a threat or a non-threat.

The aforementioned change was very slight. For certain portions of the course, using silhouette (non-threat) targets, shooters were told to draw and cover their targets when they turned rather than immediately shooting the targets when they turned. The stimulus to shoot the target was an audible command that followed at a random interval. Shooters were told in advance of the change and were reminded of the change prior to the stage of fire. What happened was very interesting.

instructor unintentional discharge

Unintentional discharge by an instructor in a range building. Bullet struck the deadbolt lock. If you think it can’t happen to you, it is more likely that it will!

During daylight qualifications, roughly 10% of shooters committed an unintentional discharge. They fired on the target when it turned just as they had been conditioned. Under low-light conditions, the change required officers to activate their light when targets turned. Again the stimulus to shoot the target was an audible command that followed at a random interval. The percentage of UDs went up slightly during low light. The other interesting observation was that the primary offenders of the daylight UDs were rookie officers, while the primary offenders in low light were veterans. I hope to do more study on this in the future, but the findings are important because any unintentional discharge is one too many. (Prior to the change in the courses of fire, I do not recall any UDs in qualifications over roughly a 12-year period.)

Act Responsibly

It is my contention that as long as you are aware of the many potential causes of an unintentional discharge and accept the fact that no one is immune to the commission of that hideous offense, then in all probability it won’t happen to you. As soon as you become too confident, too arrogant, or just don’t believe in the mutant cousin living under the basement stairs, that is when you are most at risk. Firearms ownership is a solemn and individual responsibility. It is incumbent upon us all to train responsibly, practice responsibly and carry responsibly, so that we are a positive contribution to our families and communities.

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31 Responses to “Unintentional Discharges: The Mutant Cousin Under the Basement Stairs”

  1. Jim May

    It seems to me a large percentage of these unintentional discharges would be avoided by using guns that are double action/single action since the first shot requires a longer trigger pull. Combine that with dropping the hammer when not actively shooting (via the gun’s safe hammer drop and I believe almost all unintentional discharges would be avoided.

    • William D Gerdsen aka OG

      I may have related this in the past; however, being hired to paint a bedroom including
      the closet. It was full of stuff. Piled stuff on the bed and found a pump shotgun standing in the corner of the closet. Did not think anything of it, picked it up and as putting it on the pile must have brushed the trigger. “BOOM” scared my socks & other issues took place. the OO buck went through the wall, across the room and out the window frame. No injuries thankfully but a hard lesson learned. Bill Gerdsen

  2. Rusty

    Good advice.
    Some other things to consider:
    I have had an unintentional discharge when a rifle safety failed and jiggled loose. It seems unwise to totally rely on such a mechanical gadget.
    Shooters who are left eye dominant but right handed have to make an adjustment in their basic grip……..in my case this makes it impossible to change my finger position, from inside to outside the trigger, without moving my grip. This means that the basic safety drill has to be modified. Maybe I should have my trigger guard expanded?
    For me personally I find there is too much emphasis on speed in self-defense training. My reading of the literature seems to show that there is seldom any need for super-fast weapon handling, and that I do better to train for being careful, deliberate…….and safe. “Speed Kills”……….or certainly distracts.

  3. Baron

    I’ve had two, both on lever-action rifles. The first was when I thought I’d ejected all the rounds and elected to lower the hammer by pulling the trigger. I’d miscounted, and the last round was in the chamber- BANG! The second was when I knew the round was in the chamber and elected to lower the hammer manually and it slipped away from my finger in the process- BANG! Two lessons learned, the first being to check the chamber before lowering the hammer. The second is not to trust my arthritic finger, so my lever guns are the ONLY ones I carry or stage without a round in the chamber, and I never manually lower the hammer on a lever gun anymore.

    • Todd

      Baron, thank you for sharing your comments. I recently purchased some older lever action rifles and while my newer (hand) guns have decockers, these do not, so I could see my sweaty thumb slipping off the hammer while trying to “gently” lower it. Your information will prevent the potential of a “negligent” discharge, at least from me. PS – I don’t agree with the term unintentional unless it is a true firearm malfunction, which do happen, but are extremely rare compared to negligent discharges.

  4. John Swaringen

    I had an unintentional discharge two days ago. I was cleaning my AR and had it in the vise. I had removed the takedown pin and had it separated. I realized I didn’t have it on safe so I put it back together and tried to put it on safe it wouldn’t let me. So I pulled the trigger thinking I it was keeping me from switching to safe. The round went off. Through two walls and lodged in the wall on the patio. I’m lucky that I and others are alive. That’s one mistake I won’t make again.

    It just goes to show that nobody is immune to accidental discharge, no matter how careful you are!

  5. Gary Katz

    Assuming proper trigger discipline, is it safe to keep a semi-auto compact, such as a Sig P365, in a good quality pocket holster, with a round chambered? I’d hate to think that getting jostled or falling could cause a discharge!

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  6. Mike Smith

    Thank you Mr. Nable for a very interesting and informative article. As a competitive shooter I have seen quite a few unintentional discharges (all of them in the act of clearing their gun), as an firearms instructor I, thankfully, have not had a UD, but I am very aware of how it can happen with Contralateral contractions and Trigger reassurance. You have given me lots of additional information for me to be aware of and use in my instruction. Thank you very much. I am also most interested in the reason behind the government study of 267 shooting incidents (was there some special reason for these incidents were studied?

  7. Dean Dearborn

    Excellent article! Thank you for sharing new information (to me at least), and promoting safety awareness! Learning is for a life time. It is wise to be mindful of things we cannot predict or control.

  8. Walter E Beverly III

    There is NO SUCH THING as an “unintentional discharge.” Each and every such incident is due to the NEGLIGENCE of the shooter. The correct term is NEGLIGENT DISCHARGE.

    • JP

      Yes- It may be unintentional, but it is still negligent. We called it (at least use to) a negligent discharge in the U.S. Army and also in the British (UK) Army.

  9. John Decker

    There are two kinds of discharges, intentional and negligent. If your gun fires when you did not intend it to, you did something wrong. That’s negligent. You weren’t careful enough.


    Our dad took my brother and me to Junior NRA training as kids — great muzzle awareness & basic safe handling for long guns. As an adult decades later I was sobered by a police demonstration of active shooter danger at my job. I took training w NRA instructor for pistol handling & safety, got my CCW permit, and started practicing at a range. It’s clear that you need “scenario training” more than shooting defenseless paper targets. This year I’ve been seriously hampered by arthritis and now prep for cancer radiation therapy, and the Stinking Covid. Because of temporary weakness & balance issues, I’ve stopped carrying, because I can’t get to a range, and don’t think I can handle the weapon safely until I’m finished with the treatments. Really looking forward to the day I can return to the range, and get further training.

    Don’t want to argue with people who want to GUILT me for not carrying every damn day.

  11. David

    I’m a 30 LE veteran and firearms instructor for 25. When I started we carried pistols called revolvers with long trigger pulls. We then switched to DA/SA autos. UD we’re very low. Today most carry striker fired pistols with fairly short pulls. I believe this contributes to the increase in UD’s. With proper training a shooter can shoot a DA weapon just as well a they can a striker fired gun. It takes training which takes money and good instructors. I glad to see others are concerned about something I’ve believed was a problem. Officers can be conditioned to keep the trigger finger alongside the frame but it requires targeted training

  12. Doc

    I had two in my 50 yrs of owning and using firearms. One while in my 35 yrs in law enforcement and one as an instructor recently. I learned from both those mistakes. Thankfully my training did have my weapon pointed in a safe direction. Only thing harmed was my ego in the first one. My fingers on my left weak hand on the last one. Never be complacent. First one cleaned my Glock was a weak hand slide rack finger off the trigger round went off. Grip was weak so finger had to have slipped onto the trigger. Second a new gun. Had shown it to several friends over couple weeks. I don’t keep ammunition in the training area. An NRA instructor friend called invited me to accompany him to a training session the next morning leaving early. I went and loaded the new gun placed it in my safe so I would be ready to leave early. My son dropped by. Had not seen him for awhile. We were in my training area I failed to drop the magazine I had shown so many times empty. Habit I pulled slide back showing no round in the chamber and released it pulled the trigger. I knew as I pulled the trigger I had just put a live round in it but my habit bit me as I couldn’t stop myself. My left actually reached to grab it as it went off. Hot gasses burned two fingers at the ejection point. In mind that gun was never loaded. It was new. I don’t keep ammo down there. I have changed my habits back to basics. I question myself all the time now as I get older. I fight being complacent.

    • barry vanover

      Sir, The one and only UD was similar to the later of yours. I’m not a instructor but have handled firearm’s from the age of 8.My dad (and the USMC/US army) taught me safety from the age of 6 or so. My problem was clearing my weapon talking and having 2 mags in my off hand while doing so. To make a long story short I was distracted and cleared the chamber with a mag most of the way in. Luck and good habits made it just embarrassing as I pointed it in a safe direction down range and discharged the weapon. it can happen! by the way I’m 57 so close to 50 years of experience. Moral of the story good habits kept it from being worse than it was.

    • Bill Carter

      When I was a young sailor stationed in the Panama Canal Zone, I went to my Chief’s office to get 1911 .45 pistol to perform destruction of classified material by burning. The Chief pulled a .45 off the wall and jacked back the slide to check that the chamber was empty. He did not eject the magazine and before I could yell “stop” he released the slide, which chambered a round, pulled the trigger and put a hole through the building’s roof. SCARY!

  13. David Modrinski

    Something that I am aware of but rarely incorporate into my training. I am well conditioned to keep my trigger finger up at all times and I practice by always going from that position to firing but UD is not part of my drills but definitely will be now. Thank you for this thought provoking info!

  14. Larry

    Never be overconfident when it comes to safety. We all make mistakes there. That being said always practice the finger off the trigger when handling, holding, holstering, and or pointing a gun till you are ready to fire. I never chamber a round until I plan on shooting and keep my safety on at all times. Many would be “experts” have flamed me by telling me I am stupid for not always being ready to pull and fire. They believe that when the situation arises to draw your weapon the extra time it would take to pull the safety off and chamber a round would be too costly and disasterous or deadly! First of all I don’t plan on playing cop. I am not out there stopping crime unless doing so will keep my own loved ones from being harmed. Hopefully I never am put in that situation and will avoid at all costs but on the chance I am caught up in that scenario, I will be able to react with precision. Armed robberies and the like are for trained professionals not for just trained gun owners. My gun is for mine and my family members protection and nothing else. The chance of unintentional discharge while in public is much too great a risk to do otherwise. IMO

    • DOUG

      I would never call anyone “stupid” for committing a safety compliance but do think of this; As civilians we are necessarily very close to people throughout our day. It is most likely that a defensive scenario will happen within 10 feet. I have seen several videos that portray empty chamber carriers becoming involved in hand to hand combat to the point that even if they could draw their pistol it would be impossible to manipulate a semi-auto slide to chamber a round. If you want to carry empty chamber then polish your hand skills to be able to effectively break contact with a hyper-aggressor who will quite probably be raining blows upon you with murderous intent.

  15. Lauretta

    I now get why I accidentally kept shooting the same guy the one time I went paint balling in grade school. I knew the guy was behind cover and each time I snuck up on him, I got startled and accidentally kept shooting him point blank. As a new individual to the firearms world, 8 have 10,000 index finger off the triggers to practice… Interesting article. Would be interested to hear it expanded even more.

    Another suggestion for some good PDN videos would be if Rob acted out some role play scenarios front to back so that we could see how he interacts with different malicious individuals, what might be some good ways, or things to avoid that might aggravate the situation. And then a call to the police afterwards. Just so that we can start getting familiar with some scripts beyond individual concepts in a big-picture sense. Videos are great and Rob has a nack for teaching. A great community service for us all.

  16. pjocampbell@yahoo.com

    The unintentional discharge is a scary thing to even think about. My instructor always said a holstered gun is a safe gun, particularly if you are moving/jumping. Since he only had 2 of us in his class it was easy for him to correct us on trigger finger position. Not everyone has the luxury of a good instructor and almost one on one instruction. This is an excellent article and gives everyone something to think about. Thank you!

  17. Joseph

    To make personal defense a science that we are constantly gaining more knowledge about is a good direction for us all. For us as a community to strive to be the best trained people goes a long way to promote all of us who choose to carry.
    Yes knowledge is a excellent thing but I don’t believe that alone will help. If it can happen it will happen and now I know it can happen, so I need a whole lot more training.
    The author says he hopes to do more study about this in the future, I hope he does, I am interested to understand more.

    • Tommy

      That’s because it’s not an unintentional discharge it’s a negligent discharge safety first