Evidence or studies on trigger control

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tipoc

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In another thread, closed now, a contributor made frequent reference to studies that have shown, or proven, that different trigger pulls (da, da/sa, single action, "safe action" as in the Glock, etc.) make no differences in the types of reported unintentional discharges which occur.

In one case the forum member stated:

Trigger control - we see that if the gun is hot (meaning ready to fire), trigger pull is largely irrelevant from the research.
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As I understood it the claim was that "studies have shown" that there is the same rate of unintended or negligent discharges across all types of semi auto pistol actions and da revolvers.

I'm looking to hear which studies these are and where can I read them? Could references be given for them or links provided.

This is not an attempt to reopen a thread only to seek the source of the stated opinion.

tipoc
 
I think these arguments tend to underestimate the human factors.

The studies are always interesting, but by necessity they can not tell the whole story, due to the fact that they need to be limited in scope to produce usable data.


Safety is a balancing act of built in features and user proficiency.

No safety feature can prevent all problems or compensate for poor user handling due to lack of training or other factors. Sometimes increasing safety in one manner can increase danger in another. With the relationship of trigger pull to accuracy being an example. Increase weight and you can reduce the effects of poor trigger discipline, but increase the potential for reduced accuracy.


I remember reading these studies several years ago, but can not remember the source unfortunately. As I said though... One must keep in mind the limited scope these studies entale, and must learn to filter out the facts presented and what they point to directly, from any drawn or inferred opinions presented that go beyond the studies scope. Some researchers will try to draw broader conclusions than the study can support based solely on its gathered data
 
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I have not seen the studies, but I suspect they were primarily of AD/ND's involving police. The reason is that those are (or should be) reported, while ones by citizens usually are not unless they result in injury or death. If I am correct, those studies would be heavily weighted toward those guns most carried by police (e.g., Glocks). While the same weighting might apply to citizens, there is no way of knowing. Certainly some guns, like revolvers, would tend to be more common in citizen use than in police use today.

In brief, I would have to see both the raw data and gun population data before making any judgement on the guns or type of guns involved in AD/ND firings.

Jim
 
From the second link:

For an average man (20-45 years, 170 lbs, 5ft 10 in), peak handgrip strength is about 125 lbs (Bemben, Massey, Bemben, Misner, & Boileau, 1996). The index finger contributes between 30 to 60% of the force to peak grip strength, depending on the position of the thumb and the width of the grip (Li, Latash, Newell, & Zatsiorsky, 1998; Radhakrishnan & Nagaravindra, 1993; Talsania & Kozin, 1998). Based on an average index finger contribution of 45%, the index finger in opposition with the thumb is capable of exerting
56 lbs of force during a maximal handgrip contraction. Because several studies indicate that a sympathetic contraction in hand muscles can reach 25% of maximum in laboratory settings (Shinohara et al 2003; Zijdewind & Kernell, 2001), a maximal sympathetic contraction would involve an index finger force of about 14 lbs, which is sufficient to overcome most trigger pulls on handguns.
This value, however, probably underestimates the actual maximum force that can be achieved by the index finger during field operations due to the modulatory effects of stress on muscle contractions (Christou et al., 2002; Delwaide & Toulouse, 1983; Noteboom, Barnholt, & Enoka, 2001; Weinburg & Hunt, 1976; Williams & Barnes, 1989).
 
It might be science, but it doesn't answer the question as to whether a heavier or lighter pull, or longer or shorter pull is desirable from a ND prevention standpoint.

I'll highlight a different part of the passage:

. . .a maximal sympathetic contraction would involve an index finger force of about 14 lbs, which is sufficient to overcome most trigger pulls on handguns.
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And we are only talking about men, when women would likely exhibit a lower contraction limit.

Keeping in mind that adrenaline could cause "superhuman" trigger pull strength in some cases, surely no one is going to assert that every ND ever in the history of police work was in the heat of the moment.

Certainly a percentage of them are in training, on the draw, when holstering, or the result of trying to ill-advisedly catch a fumbled firearm, carelessness, goofing off, drunken off duty mishaps, and so on.

Which then begs the question, on a sidearm lacking an external safety, is it better to have a 5.5# short stroke trigger or one with a longer travel and heavier weighted trigger.

It would seem logical that between 14 lbs and a longer travel and 5.5-6.0 lbs on a short stroke that some of the situations that result in an ND are not going to occur as readily on the more deliberate trigger than on the lighter one.

For instance, I've never heard of a toddler shooting a revolver owner to death or paralyzing them with their own piece.
 
You are arguing for very limited and rare instances... the exceptions, and not the rule.


Intuition does not always work, it can let you down at times. You have to apply the data directly.
 
And we are only talking about men, when women would likely exhibit a lower contraction limit.

Keeping in mind that adrenaline could cause "superhuman" trigger pull strength in some cases, surely no one is going to assert that every ND ever in the history of police work was in the heat of the moment.

Certainly a percentage of them are in training, on the draw, when holstering, or the result of trying to ill-advisedly catch a fumbled firearm, carelessness, goofing off, drunken off duty mishaps, and so on.

Which then begs the question, on a sidearm lacking an external safety, is it better to have a 5.5# short stroke trigger or one with a longer travel and heavier weighted trigger.

It would seem logical that between 14 lbs and a longer travel and 5.5-6.0 lbs on a short stroke that some of the situations that result in an ND are not going to occur as readily on the more deliberate trigger than on the lighter one.

For instance, I've never heard of a toddler shooting a revolver owner to death or paralyzing them with their own piece.
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I trust you will forgive me for not letting a toddler play with any of my loaded revolvers. :eek:

The next sentence after the 14lb mentioned in the study was: This value, however, probably underestimates the actual maximum force that can be achieved by the index finger during field operations due to the modulatory effects of stress on muscle contractions (Christou et al., 2002; Delwaide & Toulouse, 1983; Noteboom, Barnholt, & Enoka, 2001; Weinburg & Hunt, 1976; Williams & Barnes, 1989). so folks with below average strength could have the same problems with unintentional discharge as those with average or better hand strength.

It could be that a heavier trigger pull might reduce the chance of an unintentional discharge in some situations but the point is that it's possible for it to happen no matter the amount of force it takes to pull the trigger if the finger is on the trigger. We could up trigger pulls to 45 or 50 lbs and that might make it unlikely to have unintentional discharges when our finger was on the trigger when it should not have been. It might also make it difficult to hit what we are shooting at and more likely to hit an innocent bystander in a defensive shooting.
 
There is a purpose to guns... long stiff triggers are difficult to shoot accurately, defeating the prime purpose. The "safest" trigger would have a 2+" pull and need 70-80 pounds to move it, but could 99.999% of us even shoot it?

For me, a 4-6# pull with moderate pull length is safe. Especially w a mechanical safety. I prefer a 1911 type wide enough for the thumb to ride. Ymmv.
 
For instance, I've never heard of a toddler shooting a revolver owner to death or paralyzing them with their own piece.
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I knew a man that had a close friend who worked for S&W not too much before they incorporated the much maligned internal lock into their revolvers. During that time S&W conducted a study to see if a young child had the grip strength to pull a DA revolver trigger. In truth no, with one hand the index fingers of the children tested were not able to pull the trigger. However, the children, under no outside direction, merely used the index fingers on both hands while holding the revolver with both hands. Children are amazingly good problem solvers (I once disassembled the grearbox of an exercise bike, according to my mother, using my stubby finger to twist the nuts).

The end conclusion was that a DA pull is not enough in and of itself to stop a child from discharging a firearm. Of course this is second hand information so take it for what you will. I sometimes see owners of pistols with DA trigger pulls at stores telling others that they feel better in their purchase because their children won't be able to pull the trigger. The real answer is to secure your firearms and teach your children.
 
My read of 2damnold's three relevant links is that science has recently confirmed common sense, which seems to be less common today than it was when I was taught firearms safety half a century ago.

Science has shown that, despite training to the contrary, trigger fingers tend to far too frequently stray, unintentially and unknowingly, onto the trigger, and can unintentionally and unknowingly apply enough pressure to pull a commonly heavy DA trigger weight. It appears no one has done a controlled experiment to determine the effect of trigger pull length, but it is reasonable to assume that a longer pull is safer than a shorter one, because the longer pull affords more time to inform the inattentive mind that an accident is imminent.

cougar, you are correct in pointing out that a long and heavy trigger pull (mostly the heavy part I think) cripples the accuracy and precision of a firearm, but a designer must make tradeoffs. The safe but inaccurate long and heavy DA trigger pull on a DA/SA revolver can mitigated by cocking and shooting with the shorter and lighter SA trigger pull. This, however, apparently resulted in NDs, which led some police departments to issue hammer-shrouded DAO revolvers. The safe but inaccurate long and heavy DA trigger pull on a DA/SA semiauto pistol has to be tolerated for just a single shot, while the follow-on shots in the magazine are accomplished using the shorter and lighter SA trigger pull.

It's amazing to me that the US Army forced John Browning and Colt Arms to add a thumb safety to the M1910. The Army did not have the benefit of hard science to support its common-sense decision, but science, nearly a century later, has validated its decision.

In 1910, the Army used the example of a cavalryman needing to safely reholster his pistol while atop an unruly horse. The Army somehow knew that a trooper, no matter how well trained, could not be assured of his finger not touching the trigger with enough force to fire the gun. Some of the work 2damnold has brought to the thread shows us that other actions -- eg, startlement, loss of balance, performing tasks with limbs other than the one holding the sidearm -- can result in the trigger finger being unintentionally and unknowingly translocated to the trigger with enough force to fire the gun.

"Keep your booger hook off the bang switch" alone may work at a traditional gun range or while cleaning your gun at home, but science has shown for a decade that it is not enough alone to prevent NDs during activities reasonably anticipated to occur during policing, combat, or self defense or training for such purposes.

Ignore science-supported common sense at the risk to yourself and those around you.
 
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The end conclusion was that a DA pull is not enough in and of itself to stop a child from discharging a firearm. Of course this is second hand information so take it for what you will. I sometimes see owners of pistols with DA trigger pulls at stores telling others that they feel better in their purchase because their children won't be able to pull the trigger. The real answer is to secure your firearms and teach your children.
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The DA revolver in this case is safer than the "safe action" Glock, or other similar designs, by affording the authorized user precious time to correct an imminent tragedy.

Yes, keeping a firearm out of the reach of children is the best answer, but the common refrain in ND cases are humans making preventable mistakes.
 
The DA revolver in this case is safer than the "safe action" Glock, or other similar designs, by affording the authorized user precious time to correct an imminent tragedy.
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How much time exactly? A few seconds, maybe a minute will save the child's life? That's quite the assumption. I'm sorry, but a firearm with an unattended child is dangerous one way or the other.
 
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Limn...

Your argument for safeties is centered on carry related issues... (Your mounted calvery example) Carry is only part of the ND problem.

A safety does nothing to prevent a ND when the pistol is drawn and made ready for use.


So a safety can make reholstering a pistol less prone to screw ups... Ignoring the fact that you are assuming the user remembers to put the safety on.

If a trained user can forget to keep their finger off the trigger, they can be reasonably believed to forget the safety.

If a user can forget the safety, they can forget to leave it on when the pistol is drawn. (Ignoring that leaving the safety on is against all training on combat use of a firearm)

Its a simple matter of realizing that all safety measures can be defeated, ignored, or forgotten... Resulting in a ND.

No safety devices are foolproof, and no safety devices can be put on a firearm to prevent all accidents.

You might can remove the firing pin... But there is nothing you can do to make a firearm both 100% safe and ready to fire.


The only safety devices that have any chance at being effective are the passive safeties that require no user intervention. So safeties that prevent leaving a loaded mag and or pulling the trigger to field strip are useful in stopping most but not all NDs related to those activities.


The studies linked in this thread show that the long heavy trigger pull argument is invalid.

We all know kids will find a way to cause mischief in a short timeframe, so the long heavy pull is invalid there as well.

Manual safeties are just as vulnerable to user error as not having one.

Even by evoking technical means, there is simply no reconciling the fact that the 2nd amendment allows us to own objects which are potentially dangerous, and that those objects can be had by the untrained... to counteract such lack of training.

A firearm in the hand of an unskilled/untrained duffus is a hazard, and no amount of doodads will make it less so.

All firearms are potentially dangerous when misused... End of story...

It is pure speculation to assume any safety will be effective at stopping NDs insignificant amounts, and that the absence of those safeties increases the chances of NDs a significant amount.

Being that NDs are highly situational, its hard to test for these factors in isolation. Something that is vital to show a causal relationship between phenomenon. Something that works in this situation may not work or worsen the problem in another.


Remember... The fact that the earth was flat was "common sense" for most of human existence.
 
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How much time exactly? A few seconds, maybe a minute will save the child's life? That's quite the assumption. I'm sorry, but a firearm with an unattended child is dangerous one way or the other.
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Everyone will agree that any firearm in the hands of an unattended child is dangerous, but the point being made is there is a matter of relativity. For example, a handgun with a short and light trigger pull is more dangerous in such a situation than is a handgun with a long and heavy trigger pull. That's not an argument for arming toddlers, but an example of comparative safety. Just like there is no such thing as a perfectly safe automobile on the road, there is no such thing as a perfectly safe sidearm being carried. But, everyone has to acknowledge that some cars are safer to drive than others, and it makes sense that some handguns are safer to carry and handle than others.

For purposes of this discussion, I'm willing to stipulate that there is no such thing as a totally unsafe handgun or car, but I'm dismissing the idea that anyone here would be foolish enough to carry a knowingly grossly defective handgun or drive a knowingly grossly defective car.
 
That's not an argument for arming toddlers, but an example of comparative safety.
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Possibly, but we have to be mindful of the relative difference. In the case of the child if the child is left alone for a long enough time (the determination of that time being the important question), he/she is potentially dead either way. Frankly I don't know how much time it would take a child to figure out how to use multiple fingers. It may be a matter of a few seconds or many minutes, likely depending on the child. If my child is dead will I feel better knowing it took him/her say twice as long to kill himself/herself? Probably not. Similarly, if I crash at 100 mph into a tree I am likely dead, same as if I hit it at 200 mph. The difference being at the slower speed I have more time to react. That I grant you. But the relative time difference is the key and there is a lack of evidence beyond anecdotes and assumptions as to if that time difference will be lifesaving.

When it comes to firearms and access to children, the goal should be prevention and not reliance on a heavier trigger pull to stop a tragedy.
 
Yes, anecdotes and speculation do not make for good reference.

And as I said... Its all situational.

A child grabbing a revolver may take a certain amount of time more to figure out or somehow pull the trigger, over a lighter shorter trigger... But then it becomes simply a happenstance on if you catch them in time. Maybe you get there in plenty of time, maybe you hear the bang and come running, and maybe you walk in just in time to witness the tragedy.

Is 30 seconds of leeway better than 10 in such a situation... Yes...

But at that point you are arguing minor differences. Yes they can have big differences in result, but you can't predict nor account for every possible situation.

A line has to be drawn at some point. You have to pick your priorities. Sometimes two priorities will be at odds in the design. (Like... Strength and lightweight)


No one wants to use knowingly faulty equioment, but differing design choices with different priorities does not make one faulty and another not.

That is where most of us have issue with your arguments.

One... that you claim a pistol as faulty based on your subjective preferences.

Two... That most of your arguments to justify your subjective viewpoint is based on flawed assumptions, logic, and data sets


If you are willing to accept that your personal goals and preferences are not what dictates poor or faulty firearm design... Then most of us would have no trouble with that..
 
The safe but inaccurate long and heavy DA trigger pull on a DA/SA revolver can mitigated by cocking and shooting with the shorter and lighter SA trigger pull. This, however, apparently resulted in NDs, which led some police departments to issue hammer-shrouded DAO revolvers.
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Can you name any police depts. that issued hammer shrouded DAO revolvers?
Inquiring minds would like to know!

Hammer shrouds are intended to reduce the odds of snagging the hammer spur during a draw from concealment. Generally they have a slot to allow the hammer spur to be accessed so an SA shot is still possible. A shroud serves no purpose on a uniform carry duty weapon. It does have a use for concealed carry, such as a detective carrying under a suit jacket.

It serves no other purpose, and even the ones that do not have a slot so you can cock the hammer do not serve the purpose of preventing SA fire with a DAO revolver, the DAO mechanism itself prevents SA fire.

I know of one major metro police dept that (at one time) had the SA ability removed from their service revolvers. I know of no others, and would like to hear of anyone else who did this, or issued hammer shrouded, and or DAO guns.

Yes, it is amazing how in an earlier age the US ARMY and other people could make valid decisions based on real world observed results, without a scientific study to make them feel good.

The original ARMY nomenclature for the 1911 thumb safety was "safety lock", and that name was still in use in Army manuals in the 1970s. It is descriptive, and accurate. Not all safeties are safety "locks" today. In fact, they weren't then, either.

Without an active safety (meaning one that has to be switched on and off by the shooter as a deliberate act - something outside of the normal firing grip)applied (meaning "ON"), EVERYTHING will fire when the trigger is deliberately pulled. That's kind of the point to the whole thing.;)

The pull can be intentional, or unintentional. It can even be done by a foreign object. Unintentional (and foreign objects) we generally call "accidental". We also call them negligent. Accident implies no one is at fault, but someone always is. Guns don't do anything entirely by themselves.

A trigger that has to move an inch and a half, against a 12lb resistance takes more effort than one that only has to move a third of that distance against a third of that pressure. I don't think you need any scientific study to realize this.

There is an old story (joke?) about an engineering study that "proved" a bumblebee cannot fly.

The bumblebee, however, does not know this.

Studies can be useful things, but what matters most is what happens in the real world.

(ok, yes, studies come from real world events, but the conclusions drawn sometimes do not.)

Times change, attitudes changer, some of what was good enough, or safe enough in the past is not considered such today.

Consider the DA trigger. Longer, heavier pull than an SA trigger, right? Why is this thought to be safer? Because for all those times when something "pulls" the trigger (be it a finger or a stick) without the shooters conscious intent to fire the gun, the longer, heavier pull requirement means that there is a greater chance that an accidental pull or bump will not be enough to fire the gun.

Less likely means safer, it does not mean safe.

Guns with only passive safety(ies) are thought of as "less safe", but that does not mean unsafe. It only means that fewer unlikely events have to combine to produce an accidental discharge than in a gun that also has an active safety system, properly used.
 
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