Bullet
Comparison
Microscope
Lab
Purpose
and
Background:
Microscopes
provide
a
direct
image
of
a
small
object
of
interest
that
often
would
not
...
Bullet
Comparison
Microscope
Lab
Purpose
and
Background:
Microscopes
provide
a
direct
image
of
a
small
object
of
interest
that
often
would
not
be
seen
by
the
naked
eye.
A
comparison
microscope
is
a
version
of
the
compound
microscope
that
magnifies
two
different
samples
at
the
same
time,
side
by
side,
and
can
even
overlay
one
image
over
another.
This
is
useful
for
comparing
two
bullets
or
casings
to
see
if
they
are
microscopically
similar
and
came
from
the
same
source.
When
evaluating
firearms,
it
is
essential
to
see
if
any
of
the
tiny
striation
markings
on
bullets
and
casings
can
be
matched
to
a
gun.
This
is
because
the
majority
of
guns
leave
unique
patterns
due
to
the
rifling
process
during
their
manufacture.
In
this
lab,
you
will
compare
unknown
bullets
and
casings
from
crime
scenes
to
test-‐fired
standards
using
a
virtual
comparison
microscope.
It
is
essential
that
you
follow
all
steps
in
the
procedure
and
read
all
tutorial
and
training
information.
This
lab
will
take
some
time,
but
will
give
you
some
indication
of
the
process
that
investigators
use
to
identify
bullet
and
casing
markings!
Materials:
None
needed.
Procedure:
1.
Go
to:
http://www.firearmsid.com/classroom/class_login.htm
2.
Log
in
using
the
following
login-‐key
(C44849Forensic
Science)
and
your
first
and
last
name.
Copy
and
paste
the
bolded
login-‐key
below
directly
into
the
login-‐key
space
on
the
webpage.
If
you
type
it
instead,
be
aware
that
the
login-‐key
is
case
sensitive
and
has
a
space
between
Forensic
and
Science.
Login-‐Key:
C44849Forensic
Science
Enter
your
first
and
last
name
in
the
space
where
indicated
under
the
login-‐key
space.
3.
Once
you
are
logged
in
to
our
classroom
page,
scroll
down
and
click
on
“Bullet
ID-‐VCM”.
4.
Click
on
the
section
titled
“Rifling
Impressions”
and
answer
the
following
questions:
A. The
rifling
pattern
in
the
barrel
that
fired
a
particular
bullet
can
be
determined
by:
B. Lands
and
grooves
are
measured
in:
C. Widths
of
lands
and
grooves
on
a
bullet
are
_______________
characteristics
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