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Author Topic: Trigger pull questions for the board  (Read 12340 times)

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Offline Joshua Wright

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Trigger pull questions for the board
« on: January 12, 2016, 04:34:58 PM »
Does your agency put out a range for trigger pull when there is a question of unintentional or negligent discharge?
Does you agency have a standard procedure for trigger pull written in your SOP's?

Thanks for your replies!
Josh Wright
850.322.1404
WrightForensicConsulting@gmail.com

Offline Steve Scott

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Re: Trigger pull questions for the board
« Reply #1 on: January 12, 2016, 05:10:29 PM »
Yes we have a policy for how trigger pulls are to be done, both single action and double action as applicable.
When we report trigger pull, we report 'approximately xx pounds in the SA/DA mode of firing.  We don't often report trigger pull...sometimes in suicide investigations, and then in accidental/unintentional shooting investigations.
Steve Scott

Offline Nat Pearlson

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Re: Trigger pull questions for the board
« Reply #2 on: January 13, 2016, 01:16:08 PM »
We have a protocol and we will report trigger pulls when requested - with discussion if it does not seem appropriate to the case.  We report a range with the light end being where the hammer/striker is released the low end where it holds.

Nat

Offline Carey Alvarez Bacha

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Re: Trigger pull questions for the board
« Reply #3 on: January 26, 2016, 09:11:34 AM »
Per our SOPs, trigger pull data is not routinely reported in the Firearms Laboratory report. However if there is a specific request for the trigger pull data, it will be provided. We do not provide a range of trigger pulls but instead one trigger pull value with an associated uncertainty of measurement.  See sample report wording below:

The single action trigger pull of Item Z was measured to be X.XX X.XX lbs. at a coverage probability of 95% (k=2).

The double action trigger pull of Item Z was measured to be X.XX X.XX lbs. at a coverage probability of 95% (k=2).

We measure the double action trigger pull for revolvers at each cylinder position. Our report wording for double action revolvers is as follows:
The minimum double action trigger pull of Item Z was measured to be X.XX X.XX lbs. and the maximum double action trigger pull of Item Z was measured to be X.XX X.XX lbs. at a coverage probability of 95% (k=2).

Offline Robert Thompson

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Re: Trigger pull questions for the board
« Reply #4 on: February 11, 2016, 07:59:17 AM »
I would point out that the question is "what TP measurements were observed, and if the investigation needs this information, what is the range of those values".
I would say that while it may be interesting as to what the mean (average) of the measurements which provides some information as to the TP that is typical for that firearm, isn't the more important question as to what is the range of values; most importantly for the investigation, the lowest observed trigger pull measurement?
For that reason I would report the range of TP measurements.
/R.
/Robert T.

Offline Jennifer Floyd

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Re: Trigger pull questions for the board
« Reply #5 on: February 11, 2016, 09:11:28 AM »
We have a protocol in our SOP and report a range when trigger pull is requested/as part of function testing if requested.
Jennifer Floyd
Arkansas State Crime Laboratory

Offline Nancy McCombs

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Re: Trigger pull questions for the board
« Reply #6 on: February 11, 2016, 11:30:34 AM »
We report an approximate range both SA and DA for all function tests and officer involved shootings.
Nancy D. McCombs
fateforensicinstruction.com

Offline Joshua Wright

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Re: Trigger pull questions for the board
« Reply #7 on: January 02, 2018, 02:33:48 PM »
Thanks for the replies!
Josh Wright
850.322.1404
WrightForensicConsulting@gmail.com

 

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