The Washington times., 1930-07-28
How Science Identified
Baker Death Weapon

Two factories may be much aIlKe
in several of these items, but
never in all of them-direction
of twist, amount of twist in
inches, width Of grooves. width
of lands, depth of grooves. and
caliber between the tops Of the
lands-the original bore Of the
gun.
After the barrel is rifled, a
lap" is made by pouring molten
lead around a steel rod in the
barrel, so that it takes the i'm
print of the inside of the bore,
then withdrawing it, coating it
with oil and emery. introducing
it into the gun and tapping" out
the roughneSs and burrs and
sharp edges thrown up in the
rifling process.
But the finished barrel, looking
like a mirror to the person who
casually glances through it, looks
more like a railroad switch yard
when cut open and put under the
microscope. The drill leaves
gouges that in the cheaper guns
are too deep for the roaming to
remove. The reamer leaves rings
around the finished bore which
show on the tops of the lands.
Even the final tapping with fine
emery leaves what to the eye OF
the microscope are deep grooves
parallel with the gun bore.
-
copper jacket, or Steeljacket va
riety, emerges from the barrel
bearing the imprint that is the
net result of ali Of these rough
spots, gouges, and imperfectionS.
Every bullet from this barrel, if
of factory standard in size, will
bear this identical imprint-dif-
ferent from the imprint given by
every other gun.
"Test" Bullets Shot
Given suspected murder gun,
the scientist takes bullets of the
same type as the fatal bullet and
fires them from the gun into a
wastebasket filled loosely with
cotton waste, so that the bullets
will not be marred by contact
with hard substances. The fatal
bullet and the test bullet then are
placed in what is called a com
pariSon microscope" which con-
siSt of a pair of microscopes and
a priSmatic eyepiece by which the
two fields may b. seen in one eye
piece. An identical mark on each
bullet is found for a starting place,
and the two bullets are then
turned together and examined to
see if their markings coincide.
The fatal bullet and two test
bullets then are put in a triple
holder and rotated together be-
fore camera, 20. microscopic
pictures being made around the
circumference, to show the coinci.
dence throughout.
Science. is Young
If anyone still is skeptical, he
can take one of the n pictures
of the three bullets, cut a bot:
tom section off one of the test
bullet pictures, a top section off
the other test bullet picture,
Superimpose them on the bottom
and top sections of the fatal bul.
let picture, and see how the
markings lineup with the middle
section Of the fatal bullet picture.
The science of firearms identi-
fication is only about l8 years
old. DR.. Balthazard, a French
scientist. started 1t by writing an
article on the marks of identifi-
cation on fired cartridge cases.
Judge Waite formerly of the De
partment of Justice, then started
his collection of gun specifications
obtained from factories. Because
of the influx of foreign guns
into the United States, he toured
foreign factories gathering data
and now has the most complete
collection in the world. Enlist
ing the aid of Major. c. H. God.
dard, Chicago firearm expert; !;
Phillip Gravelle, well-known
photo-micrographer, and John H.
Fisher, physicist, he evolved the
scientific apparatus for examin-
ing, measuring, and photograph
ing bullets.
IN