[FORENSIC] Glock firing pin impression
Jonathan M. Spencer
This is one for folks who are familiar with microscopy. :-)
What is special about the face of a Glock's firing pin that it leaves
identifiable marks on a fired primer? I'm not asking to match is to a
**specific** Glock, simply that the marks say **a** Glock fired it. Any
takers?
--Jonathan Spencer
==================================================================
Keith Borer Consultants - Forensic Scientists
Mountjoy Research Centre, Durham, DH1 3UR, England
tel: + 44 191 386 6107
fax: + 44 191 383 0686
==================================================================
Don Kenny
In <4okfqg$q...@xring.cs.umd.edu> "Jonathan M. Spencer"
<jona...@borer.demon.co.uk> writes:
#
#What is special about the face of a Glock's firing pin that it leaves
#identifiable marks on a fired primer? I'm not asking to match is to a
#**specific** Glock, simply that the marks say **a** Glock fired it.
Glock uses a firing pin which is somewhat rectangular in cross-section.
(must be that Austrian beer)
Cheers
- Don Kenny (dke...@ix.netcom.com)
Member: Orange Gunsite Family, NRA, CRPA
Shooting and Reloading For Nearly 40 Years
"Society Is Safer When Criminals Don't Know Who's Armed"
Frank Lindquist
I am not familiar with microscopy, but am an engineer and do own Glocks.
There are two factors that are Glock specific ...
the "firing pin" on a Glock is actually called a Striker, when the Trigger is
pulled, the first stage of the trigger pull takes the Striker from a "half"
cock position to "full" cock. During this cocking, the Striker spring is
compressed, such that when the Trigger pulled full (second stage) the
Striker is released and the Striker spring pushes the Striker foward
to impact the primer.
1. The part of the Striker that impacts the primer is not round, unlike most
firing pins in use on pistols. It is machined from the striker, having
flat vertical sides, and a triangular rounded front.
___
end view: | | Side view: \
| | \
| | ) - Primer contact point
| | /
| | ___/
2. Most pistols (Not Glock) use a hammer to impact a firing pin, and
the spring around the firing pin is used to keep the firing pin out of
the chamer until the hammer impacts the firing pin, and also to return
the firing pin to the original position; fully retracted from the chamber.
This retraction happens prior to the empty case being ejected from
a semi-automatic pistol.
A primer hit with a round firing pin, with a spring retraction system
will leave typically a circular, spherical depression in the primer.
end view: O (Non-Glock) side view: |
(
|
Unlike other pistols, the Glock uses a spring to push the Striker into the
primer. There is no spring to push the Striker back into the original
position. The primer of the empty case, upon ejection, is still in
contact with the striker. The case is pulled out of the chamber by the
extractor, and pushed out of the pistol by the ejector.
The combination of movement of the case relative to the striker, with
spring pressure on striker still in contact with the primer causes a
secondary mark on the primer ("wipe") mark.
Thus, a "wipe" mark is formed on primer, that I believe is Glock Specific.
end view: side view: | (Greatly exaggerated)
/\ / "wipe" mark
|| (
|
^
Striker center
contact point.
Peter Alan Kassler has written a book on Glocks, entitled:
_Glock, The New Wave in Combat Handguns_
I believe there is a picture of this primer mark in his book - I can check
when I get home tonight.
You may wish to contact him directly:
You can reach Peter Kasler as follows:
e-mail: t...@well.sf.ca.us
USmail: 800 West Napa Street
Sonoma, CA 95476
Voice: 707-939-0303
415-777-0303
Cellular:707-484-0303
Fax: 707-935-1713
Cheers -
Frank Lindquist
Yank ...
HerrGlock
Jonathan M. Spencer wrote:
#
# This is one for folks who are familiar with microscopy. :-)
#
# What is special about the face of a Glock's firing pin that it leaves
# identifiable marks on a fired primer? I'm not asking to match is to a
# **specific** Glock, simply that the marks say **a** Glock fired it. Any
# takers?
#
# --Jonathan Spencer
My Glock's all have very distinctive impressions on the primers. The
striker on a glock is rectangular (sp?) and I've noticed that glocks are
the only one that makes this particular shape from picking up fired
cases off the range (scientific, huh?). You don't need a microscope to
see these marks and if you see one you'll know.
I'm not a molecular-anything (my sister is into genetics and I get
briefed about whole worlds under the microscope, most of which I don't
have a clue what she is talking about) but I have more than a nodding
acquaintance with forensic science as I am an ex-cop with a strong
interest about anything chemical :)
Hope this helps
HerrGlock
Doug Owen
Jonathan M. Spencer (jona...@borer.demon.co.uk) wrote:
: This is one for folks who are familiar with microscopy. :-)
: What is special about the face of a Glock's firing pin that it leaves
: identifiable marks on a fired primer? I'm not asking to match is to a
: **specific** Glock, simply that the marks say **a** Glock fired it. Any
: takers?
You mean the rectangular (rather than round) firing pin dent? I would
guess it's the shape?
Doug Owen
Dave Croyle
In article <4okfqg$q...@xring.cs.umd.edu>, "Jonathan M. Spencer"
<jona...@borer.demon.co.uk> wrote:
# This is one for folks who are familiar with microscopy. :-)
#
# What is special about the face of a Glock's firing pin that it leaves
# identifiable marks on a fired primer? I'm not asking to match is to a
# **specific** Glock, simply that the marks say **a** Glock fired it. Any
# takers?
The striker (firing pin) leaves a unique oval-looking impression, as
opposed to the traditional circular imprint (for centerfires anyway). Once
you've seen one you'll recognize them right away from that point on. I
have several Glock-fired 9x19mm cases.
I thought I read somewhere that another handgun made similar
impressions, but it was one that came out after the Glock. I'm really not
sure about that though.
Regards,
Dave
--
-- Dave Croyle --
LGPD Disaster Aid Response Team NRA Life/SATF Charter Founder
j...@taligent.com (work) KE6QKZ croy...@best.com (home)
Arne Carlsten
: What is special about the face of a Glock's firing pin that it leaves
: identifiable marks on a fired primer? I'm not asking to match is to a
: **specific** Glock, simply that the marks say **a** Glock fired it. Any
: takers?
: --Jonathan Spencer
: ==================================================================
: Keith Borer Consultants - Forensic Scientists
: Mountjoy Research Centre, Durham, DH1 3UR, England
: tel: + 44 191 386 6107
: fax: + 44 191 383 0686
: ==================================================================
The Glock firing pin impression is rather squared-off (the pin looks more
like a piece of sheet metal than the traditional rounded firing pin),
and, at least in the .40 S&W (maybe the other non-9mm versions as well)
there's usually a pronounced wiping effect caused by the action starting
to unlock while the firing pin's still forward. Going just on naked eye
examination, there seems to be some marking of the primer by the
breechface as well. The non-9mm Glocks have pretty generous chambers, so
there's usually a bulge in the casewall where it was unsupported by the
chamber. The bulge seems to be at 6 o'clock on the couple of cases I
have handy (fired in an M22).
The firing pin wipe seems to be the quickest check, it shows the
narrowness of the firing pin very clearly.
--
Arne Gustav Carlsten
Flagstaff, Arizona
Chomh da/na le muc...
Eric Inazaki
Jonathan M. Spencer (jona...@borer.demon.co.uk) wrote:
: This is one for folks who are familiar with microscopy. :-)
: What is special about the face of a Glock's firing pin that it leaves
: identifiable marks on a fired primer? I'm not asking to match is to a
: **specific** Glock, simply that the marks say **a** Glock fired it. Any
: takers?
Glocks are unusual (unique?) in that the striker/firing pin
face has a rectangular cross section. Most other guns leave
a round mark on the primer, Glocks leave rectangular ones.
Is this what you mean?
eric
Tom Przybylski
Frank Lindquist (f...@Sun.COM) wrote:
<excellent review of Glock striker system & marks on primer
deleted>
:
: Thus, a "wipe" mark is formed on primer, that I believe is Glock Specific.
What about the S&W Sigma? Is it enough of a Glock copy to leave
the same marks on a primer? Seems like that is one gun that might
be hard to differentiate.
- Tom
Brad Higgins
"Jonathan M. Spencer" <jona...@borer.demon.co.uk> wrote:
#This is one for folks who are familiar with microscopy. :-)
#What is special about the face of a Glock's firing pin that it leaves
#identifiable marks on a fired primer? I'm not asking to match is to a
#**specific** Glock, simply that the marks say **a** Glock fired it. Any
#takers?
#--Jonathan Spencer
#==================================================================
#Keith Borer Consultants - Forensic Scientists
#Mountjoy Research Centre, Durham, DH1 3UR, England
#tel: + 44 191 386 6107
#fax: + 44 191 383 0686
#==================================================================
Instead of the regular round pin dent that
my HK and SW pistols leave, the glock
leaves one that looks like a round firing
pin in the middle of a rectangular carrier.
|-----|
| O | <--- LIke this
|-----|
Nick Passino
Sigmas leave the same oblong mark too.
--
- pas...@garply.com -
Comments or flames regarding grammar or spelling
will be TOTALLY ignored, as user is dyslexic and mildly ADD.
Comments and flames may never even get read due to same reasons.
Thank you for you're cooperation. The Computer is your friend.
Have a nice day.
Kristopher M. Means
In <4oncgr$4...@xring.cs.umd.edu> er...@howdy.wustl.edu (Eric Inazaki)
writes:
#
#Jonathan M. Spencer (jona...@borer.demon.co.uk) wrote:
#: This is one for folks who are familiar with microscopy. :-)
#:
#: What is special about the face of a Glock's firing pin that it
#: leaves identifiable marks on a fired primer? I'm not asking to
#: match is to a **specific** Glock, simply that the marks say **a**
#: Glock fired it. Any takers?
#
#Glocks are unusual (unique?) in that the striker/firing pin
#face has a rectangular cross section. Most other guns leave
#a round mark on the primer, Glocks leave rectangular ones.
#Is this what you mean?
Actually, the *tip* of a Glock firing pin is round like any other
pistol. It's the rectangular firing pin hole in the breech face that
makes the distinctive mark on brass.
Look closely at the primer - the rectangle sticks *out*, not in.
-- Kris Means
Bruce Markowitz
NYPD ballistics experts can absolutely identify a spent case as having
been fired from a Glock, and do so in Court every day.
"Jonathan M. Spencer" <jona...@borer.demon.co.uk> wrote:
#This is one for folks who are familiar with microscopy. :-)
#What is special about the face of a Glock's firing pin that it leaves
#identifiable marks on a fired primer? I'm not asking to match is to a
#**specific** Glock, simply that the marks say **a** Glock fired it. Any
#takers?
#--Jonathan Spencer
#==================================================================
#Keith Borer Consultants - Forensic Scientists
#Mountjoy Research Centre, Durham, DH1 3UR, England
#tel: + 44 191 386 6107
#fax: + 44 191 383 0686
#==================================================================
Reply here (sco...@worldnet.att.net) or:
tren...@aol.com
Jonathan M. Spencer
#What is special about the face of a Glock's firing pin that it leaves
#identifiable marks on a fired primer?
and I'm very grateful for the many informative replies I got. Thanks
once again folks.
--Jonathan
============================================================
Jonathan Spencer -- forensic scientist
Mountjoy Research Centre, Durham, England, DH1 3UR
tel: +44 191 386 6107 fax: +44 191 383 086
============================================================
Rich
sco...@worldnet.att.net (Bruce Markowitz) writes:
# NYPD ballistics experts can absolutely identify a spent case as having
# been fired from a Glock, and do so in Court every day.
#
# #This is one for folks who are familiar with microscopy. :-)
#
# #What is special about the face of a Glock's firing pin that it leaves
# #identifiable marks on a fired primer? I'm not asking to match is to a
# #**specific** Glock, simply that the marks say **a** Glock fired it. Any
# #takers?
#
# #--Jonathan Spencer
# #==================================================================
# #Keith Borer Consultants - Forensic Scientists
# #Mountjoy Research Centre, Durham, DH1 3UR, England
# #tel: + 44 191 386 6107
# #fax: + 44 191 383 0686
# #==================================================================
#
#
# Reply here (sco...@worldnet.att.net) or:
# tren...@aol.com
#
# The Glock firing pin has a very distinct impression that can easly be seen by the naked
eye.The mark left by the firing pin on the primer is very oblong or oval verticly
Rosco Benson
#"Jonathan M. Spencer" <jona...@borer.demon.co.uk> wrote:
##This is one for folks who are familiar with microscopy. :-)
##What is special about the face of a Glock's firing pin that it leaves
##identifiable marks on a fired primer? I'm not asking to match is to a
##**specific** Glock, simply that the marks say **a** Glock fired it. Any
##takers?
##--Jonathan Spencer
No microscope (or even magnifying glass) required. The Glocks have
a "chisel" shaped firing pin, that leaves an indentation that is quite
different from that left by a conventional firing pin. The only pistol
that is more easily identified by the condition of fired casings is
HK's P7. The marks from the fluted chamber make it unnecessary
to even pick the cases up to make that call.
Rosco S. Benson
NCR Customer Information Services
My opinions...not my employer's
John W. Engel
In article <4otmq9$h...@mtinsc01-mgt.ops.worldnet.att.net>,
Bruce Markowitz <sco...@worldnet.att.net> wrote:
#NYPD ballistics experts can absolutely identify a spent case as having
#been fired from a Glock, and do so in Court every day.
##What is special about the face of a Glock's firing pin that it leaves
##identifiable marks on a fired primer? I'm not asking to match is to a
#--Jonathan Spencer
It really doesn't take any kind of expert....the indentation is rectangular,
rather than round. Hi, Jon!
whit
Keith Whaley
Jonathan M. Spencer wrote:
#
#
# identifiable marks on a fired primer? I'm not asking to match is to a
# **specific** Glock, simply that the marks say **a** Glock fired it. Any
# takers?
#
# --Jonathan Spencer
# Keith Borer Consultants - Forensic Scientists
# Mountjoy Research Centre, Durham, DH1 3UR, England
# tel: + 44 191 386 6107
# fax: + 44 191 383 0686
# ==================================================================
Why does this topic generate such ongoing dialog?
Glocks have a rectangular firing pin, the nose of which is rounded off.
It sits vertically in the breech face, relative to the attitude of the
gun. Frequently (all the time?) when the gun fires, the case is still
pressed against the breech face with some pressure.
Therefore, when the case is asked to vacate the premises, the firing pin
tip, which is ALSO still sticking out some, leaves a furrow along the
face of the primer, from the center outward (upward.) Somewhere along
the primer pocket outer edges, plus or minus a little bit, the firing
pin (striker) retracts, and the furrow runs out.
SO! When one looks at fired cases, it is abundantly obvious which belong
to Glocks and which don't.
I have seen any number of cases which have firing pin "smears" but they
don't (none of them) resemble what the Glock does to them.
These easily demonstrable facts ought to put an end to it, but it won't.
What else does anyone want to know?
keith