Examination of Firearms Review: 2007 to 2010 - Interpol

ay mapping to restore or detect obliterated laser-etched firearm markings (63). It
was concluded that the use of SEM and X-ray mapping as a non-destructive
method to restore or detect totally obliterated laser-etched markings was
ineffective.
A paper by Wightman and Matthew (64) looks at the application of Fry’s reagent
to recover erased marks from steel. The novelty of this publication is that it looks
into the effect of the original stamp force on the ability to recover erased marks.
The applied force is important since this controls the degree of underlying
deformation as well as the depth of penetration. Recovery of erased marks is
difficult where low applied force has occurred. In the present study marks could
still be recovered 1.25 mm below the impression. Also the authors have noted a
degrading effect of the Fry’s reagent in function of storage time. Nowadays more
applications use high strength aluminium alloy. When engraved marks are
obliterated from such substrates, current techniques prove unsatisfactory. Bong
and Kuppuswamy have investigated what etching techniques are better in these
situations (65). It appeared that either 1/ immersion in 10% aq. phosphoric acid
(H3PO4) and 2/ alternate swabbing of 60% HCl and 40% NaOH were both quite
effective.
2.3 Legislation and other efforts
2.3.1 Microstamping
In the past years, a lot of debate has been going on regarding microstamping of
codes or serial numbers on firearm parts, more specifically the working surfaces
such as the firing pin, that are transferred to the cartridge case during the
discharge of the gun. With the AB 1471 Crime Gun Identification Act of 2007,
microstamping became legislation for the state of California. Equivalently,
Assembly Bill AB 09818 passed New York legislature. In those states and as of
January 1, 2010 semi-automatic pistols need to be equipped with a microscopic
array of characters that identify the make, model, and serial number of the pistol.
It appears that serious testing by qualified firearms examiners was negated. In
an open letter to the AFTE membership, Lucien C. Haag comments on the false
claims that were made regarding his early study of the microstamping technology
(66).
In 2008, Beddow, Howitt, Tulleners and Giusto published an extensive study on
the durability and legibility of micro-markings from firing pins (67). This second
generation of micro-engraved firing pin contains three different encoding formats:
1/ the original alphanumeric code on the face of the firing pin, 2/ either a gear
code or a dot code, and 3/ a radial bar code that extends down the side of the
pin. Overall the alphanumeric characters and the gear code structures proved to
be capable of withstanding repeated firing; however some degradation was seen
with specific firearms. A determination of what constitutes an acceptable lifespan
for these characters needs to be developed. The dot code structure was
determined to be unsuitable. The radial bar code structure exhibited varying
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