The Washington times., 1930-07-28

are so positive in their repeated
assertion that the gun Of Herbert
M. Campbell, Virginia real estate
operator, is indisputably the
weapon used in the murder Of
Mary Baker, Navy employe?
The answer is that firearm:
identification has reached
stage of scientific development
that makes it equally as reliable
as fingerprint Identification.
Shots Are Traced
Science now makes it possible
for criminologists to accomplish
four astonishing and almost I'm
believable feats:
/. Given a gun ard a bullet,
to determine unerringIy whether
the bullet was fired from the
gun.
2. Given a gun and an empty
cartridge. to determine whether
the cartridge came from the
gun.
Bullet Tells Tale
;. Given a bullet to deter
mine the make, calibers type,
approximate date of manufac.
ture, and approximate serial
number Of the gun that fired
the bullet.
4. Given an empty cartridge
case, to determine the make,
calibre, etc, Of the gun that
fired it.
Baker Gun Spanish
In the Baker case. the police
started their scientific investiga-
tion with the bullets extracted
from the body of the slain girl.
These were turned over to DR..
Wilmer Souders, Buraeu of Stand
ards physicist and ballistics en-
pert. who conducted microscopic
tests that enabled him to in
form the police as to the type
of gun used--a SpaniSh-made
gun Of 80 caliber.
This is exactly the type OF
gun that later was turned over
to the authorities by Mr.. Camp.
bell and that has been identified
as the murder weapon.
Gun Data Grows
How was DR.. SouderS enabled
to describe so accurately the type
of weapon from examination OF
a mere bullet? Thanks to Judge
c. E. Waite, of New York City
chief of the Bureau of Forensic
BalliStics and pioneer in fire
arms Identification, scientists In
this country now have accumu.
lated detailed information regard
ing every. type of gun manufac
tured by virtually every gun plant
in the world. There are no two
makes of gun Identical in every
respect, and these variations
slight though they may be, leave
their tell-tale marks on the bull
lets fired from them.
Far easier is.it to tell whether q
given bullet was fired from par
ticular gun once the gun is pro
6uced. So when police turned the
Campbell gun over to the Bureau
of Standards, DR.. Souders had sll
he could possibly ask for.
Gun Marks Lead
Scientists have proved that no
two guns, even of the finest make,
put exactly the same imprint on
the bullet passing through the
barrel Outside Of the shop dif
ferences in manufacture, distin-
gushing guns of different make,
the whole field by which a gun
and its bullet are linked lies in the
grooves cut in the bullet by the
lands" or raised portions in the
gun barrel, a field containing
enough individual burrows and
humps and clods to remove all
doubt.
A pistol or rifle barrel is made
by drilling a hole through a round
bar of mild steel, slightly smaller
than the finished caliber. This
hole is then "reamed" by means
of a cutting tool having its cutting
edges parallel with its long axis
and cutting in the direction Of It's
revolution.
No Two Alike
The reamed and apparently
smooth hole. or bore" is then
rifled or grooved, the object be,
ing to compel the bullet to spin
on its long axis and to travel
point on.
The number Of grooves is an
other item in Identification OF
the particular make of gun. The
width of the grooves and the
lands Is still another. The depth
et the groove Is q third point