Firearm
examiners routinely test firearms to determine if they function properly.
A part of that examination involves determining the trigger pull of the
firearm in question. "Trigger pull" is defined in the
Association of Firearm & Toolmark Examiners (AFTE) Glossary as:
"the
amount of force which must be applied to the trigger of a firearm to cause
sear release."
I testified in a
murder trial today where the defendant was charged with shooting his wife.
His defense was that his revolver "just went off." The
prosecutor in the case wanted me to show the jury how the revolver functioned
and a key question was whether the revolver's single and double action trigger
pulls were normal. This is a very common question when the accidental
discharge of a firearm is claimed.
There are two
basic methods used to determine the trigger pull of a firearm. One
method uses static weights that are attached to the trigger of the firearm.
Weight is usually added in 1/4 pound increments until the sear of the firearm
releases. The second method involves the use of a high quality spring
gauge. As pressure is applied to the trigger, the gauge is watched and
the amount of pressure required to release the sear is recorded. These tests
are usually repeated several times to determine an average trigger pull.
Firearm
manufacturers typically have minimum and maximum trigger pull values for their
firearms leaving the factory. Factory specifications are sometimes
available to firearm examiners; however, over time, as the action of a
firearm is "broken-in", the trigger pull can change making the
factory specifications of limited value.
I have been
conducting trigger pull tests on firearms for over 20 years. Because it
is a subject that comes up so often I thought it would be handy to make a
database application that would allow me to search through the average trigger
pull data of the firearms that have come in off the streets. The result
of which is a Microsoft Access database application I've named TRIGGER PULL
DATA SEARCH.
TRIGGER PULL DATA
SEARCH is an application that allows for searches to be made for trigger pull
data of specific firearms, models, calibers, and types. Also included
are several tables that show the average trigger pulls for different firearm
categories.
This database
contains the trigger pull information from over 9400 firearms/airguns and is a
compilation of data from several different firearm examiners or forensic lab
systems.
I want to
especially thank Stan
Berg for his contribution to the database. Stan allowed me to use
his personal database that contained the trigger pull data from over 4500
firearms and airguns. Thanks Stan! Be sure to check the
Acknowledgements page for a complete list of contributors.
NEW Version 2.1- Updated 3/12/03
New version
now available. I've added the ability to add your own
trigger pull data to the application and to export that data
back to me for inclusion into future releases of the main
application.
If you have a
database containing trigger pull data and would like to have it included in
this application please contact me via my email address listed below.
You
must have Microsoft's Access 97 or 2000/XP to use this application.
This database application will not work with earlier versions of Access.
DISCLAIMER:
This application is being provided as an educational and investigative
tool only. The data contained within this application is not warranted
in any way by the provider.
Click here to go to www.firearmsid.com to download this application
If you
have any problems running this application contact Scott Doyle.
.
Comments are not only welcome they are required!
www.afte.org
> Examiner
Resources > Trigger Pull Database
