Info on FBI study regarding trigger weight versus length of pull....

[GJM]

"I wonder if there was a study of some sort that specifically separated trigger weight and trigger pull length, which has since disappeared? Or instead did someone once make a comment that later turned the "workshop" material about trigger pull length/weight into a "study" on "trigger pull length, AND trigger weight"? That is a pretty significant drift of meaning..."

You have to remember, this is from 28 years ago. I have seen many, many subjects in this business morph into something almost recognizable over far less time.

I really doubt any major agency (fed or state) took the time to do an actual study and publish it, but Doc Roberts, Darryl, Wayne, Mas and I are all unaware of it. I don't mean to sound arrogant, but we were all in the business at that time frame.

If I were betting ten PF dollars, it would be that Tom is absolutely right with both his points. Beyond that, how would such a test be conducted, why would such a test be conducted, and how did the FBI integrate that information into their weapon selection and firearms training?

[jthhapkido]

You have to remember, this is from 28 years ago. I have seen many, many subjects in this business morph into something almost recognizable over far less time.

I really doubt any major agency (fed or state) took the time to do an actual study and publish it, but Doc Roberts, Darryl, Wayne, Mas and I are all unaware of it. I don't mean to sound arrogant, but we were all in the business at that time frame.

I believe you. [sigh] Dang it, the results Todd related matched my preconceived notions really well, so I liked them a lot.

So really, about the only research we have (versus anecdotal evidence collected over time via memories from people which may be spot-on but may also be completely useless because humans are bad at that sort of thing) is that startle reflexes can cause finger clenching with strength amounts up to far in excess of even heavy trigger pull weights, though it is highly variable and person-and-circumstance-specific.

Yes?

[Wayne Dobbs]

I believe you. [sigh] Dang it, the results Todd related matched my preconceived notions really well, so I liked them a lot.

So really, about the only research we have (versus anecdotal evidence collected over time via memories from people which may be spot-on but may also be completely useless because humans are bad at that sort of thing) is that startle reflexes can cause finger clenching with strength amounts up to far in excess of even heavy trigger pull weights, though it is highly variable and person-and-circumstance-specific.

Yes?

Here is the definitive peer reviewed, scientifically done, paper on the various ways (there are three) you can have an involuntary firearms discharge:

"Involuntary Muscle Contractions and the Unintentional Discharge of a Firearm"; Roger M. Enoka, Ph.D. Department of Integrative Physiology; University of Colorado, Boulder, CO Corresponding Author: Roger M. Enoka, Ph.D. Department of Integrative Physiology; University of Colorado Boulder, CO 80309-0354, USA

Text available at: https://fortress.wa.gov/cjtc/www/ima...0Resources.pdf

Here is a European police study of the same topic:

http://www.ncbi.nlm.nih.gov/pubmed/17063958

[GJM]

Wayne, can you provide the cliff notes summary?

[Wayne Dobbs]

Wayne, can you provide the cliff notes summary?

Yes. Trigger fingers on, in line with, or in proximity to triggers can, will and have actuated those triggers INVOLUNTARILY (as in the brain was not involved) when one or more of the following situations occur: startle event, sympathetic contraction by the gun hand and trigger finger due to an off hand maximum grip event and a loss of balance event. The grip efforts during some of these events approached 50 pounds of trigger pull. You cannot train this out of your being and you cannot install a trigger that will prevent occurrence of these events. You must keep trigger fingers in register on the frame ABOVE the trigger guard (not in line with the trigger outside the trigger guard either) until you have a cognitive decision to fire the weapon and the weapon oriented on the target.

This paper was originally published about 1985 by Dr. Enoka and is the landmark work on the problem. The European study simply applied more specific instrumentation to Enoka's findings. I've noted that the link to the Euro study may be difficult to access. If needed, I can email a PDF of that study.

[GJM]

Thanks, Wayne.

[Clobbersaurus]

Office of Inspector General - County of Los Angeles - 52 page report

https://oig.lacounty.gov/Portals/OIG...e%20Report.pdf

Thank you for posting this link. I found the below very interesting:

The OIG found that as soon as widespread use of the new gun by field deputies commenced, there was a marked increase in tactical unintended discharges – that is, deputies firing weapons without intending to do so during police operations. In 2012, just before the M&P became standard issue, there were three tactical unintended discharges. In 2013, there were nine. In 2014, after substantial adoption of the new weapon in patrol settings, there were nineteen tactical unintended discharges, over a 500% increase when compared with 2012.

[John Hearne]

when one or more of the following situations occur: startle event, sympathetic contraction by the gun hand and trigger finger due to an off hand maximum grip event and a loss of balance event. ... You cannot train this out of your being

I'm not trying to argue just adding some detail:

You can also get trigger finger contraction when your hands are not on the normal side of the body. The classic example of this is Harries flashlight technique. For the right hander, the gun is now on the left side and the flashlight is on the right. If the Harries is a novel experience or it hasn't been trained for awhile, you can get contraction in the trigger finger when you activate the flashlight.

While I can't cite author, title, and page number, I did find a reference that training can mitigate the factors that Enoka identified. The problem is that the training is very sensitive to recency effect. So technically, you can train to mitigate it but it takes a lot of effort. You're better off just keeping you finger off of the trigger.

[Wayne Dobbs]

I'm not trying to argue just adding some detail:

You can also get trigger finger contraction when your hands are not on the normal side of the body. The classic example of this is Harries flashlight technique. For the right hander, the gun is now on the left side and the flashlight is on the right. If the Harries is a novel experience or it hasn't been trained for awhile, you can get contraction in the trigger finger when you activate the flashlight.

While I can't cite author, title, and page number, I did find a reference that training can mitigate the factors that Enoka identified. The problem is that the training is very sensitive to recency effect. So technically, you can train to mitigate it but it takes a lot of effort. You're better off just keeping you finger off of the trigger.

Enoka also confirmed one to me a couple of years ago about impacts to the gun arm being associated with an ND. You're right, John: keep your finger off the trigger and out of line with it.

Also correct on the flashlight/opposite side issue. Darryl had a case in his agency where an officer under stress of conducting a hot stop, keyed a radio mike and ND'd a round DA round from a Sig 220.

[psalms144.1]

Also correct on the flashlight/opposite side issue. Darryl had a case in his agency where an officer under stress of conducting a hot stop, keyed a radio mike and ND'd a round DA round from a Sig 220.

Unpossible! Everyone on the interwebz knows you can only ND with a GLOCK...