October
23, 2002 9:00 a.m. Not
So Fast
Ballistic
fingerprinting won’t work in response to the D.C. sniper.
By Dave Kopel
& Paul H. Blackman
he Sniper has
reinvigorated gun-prohibition groups. Gun control is the answer for them,
of course, to a murder spree by someone using some kind of rifle or handgun
in a caliber of approximately .223. The prohibition lobbies and their
media dupes are calling the suspect .223 "high-powered," but
it's really about as low powered as a centerfire rifle gets. As a hunting
round, it's for varmints, not big game. While the Violence Policy Center
has been making a big deal about "sniper rifles" and "sniper
culture" (thereby denigrating the many decent people who serve as
snipers for the police or the military), the .223 caliber — if that's
what the shooter is using — is quite far from the long-range, high-power
type of rifle used by police and military snipers.
Thus,
the gun-control issue du jour is so-called "ballistic fingerprinting"
or "ballistic DNA." The theory is that when a bullet goes through
a rifled barrel — handgun or rifle — striations are made on
the bullet that are unique to that particular barrel, just as DNA and
fingerprints are unique. So, once you have a crime bullet, all you need
to do is compare it to all other bullets, find your match, and go from
there, just as you would do with a fingerprint or DNA sample.
Note the first obvious problem: You need something to compare it to. Some
law-enforcement officials would probably like it if they had computers
files of everyone's fingerprints and DNA, and such a database would certainly
help solve many crimes. A scheme for collecting such private information
from every household in the United States would be politically impossible
currently — but once the privacy of half of all American households
that own firearms is breached, then breaching the privacy of the other
half of households may be politically easier.
Supposedly, the government can collect a barrel print from every gun,
or at least every new gun, and then a crime bullet can be compared to
the sample. Obviously, that also requires knowing who owns each gun associated
with a particular bullet, which is one reason why the program requires
universal gun registration. If it's okay to require that all rifles and
handguns be sampled and clearly associated with the owners who own the
barrel that can make such markings, it hard to see why it would not be
okay to require fingerprints and DNA samples from everyone. There are
far more crimes that can be solved with fingerprint or DNA analysis than
with bullet-striation analysis.
Indeed, the case for fingerprint/DNA collection is stronger than the case
for collection of bullet markings; fingerprints and DNA are immutable,
and thus very useful for criminal investigations. But barrel markings
change. They change over time, microscopically with each firing of the
gun; for inexpensive guns with softer metal barrels, 50 or 100 rounds
can change the striations. If 1,000 rounds are fired through the gun (as
would be common during a long weekend of serious target practice), the
changes are all the greater. In addition, scraping the inside of the barrel
physically or chemically can deliberately alter barrel markings.
Finally, for many guns, the barrel can be changed entirely. Barrels are
commonly available after market components. Gun owners often buy replacement
barrels to improve a gun's performance, or to replace a barrel that has
been worn out by heavy practice. For guns that have integral barrels that
can't be switched out, the barrel can be rebored — as is often done
for a gun that has been worn out by heavy use.
Even if we somehow register and collect data from every new rifle and
handgun, from the many tens of millions of rifles and handguns currently
in private hands (including guns owned by criminals), and from the unknown
number of spare barrels currently in private hands, and even if there
were some magical way to prevent gun barrels from being altered by scratching,
there's the problem of shotguns. Unlike handguns and rifles, shotguns
are not rifled; that is, they do not have grooves in their barrel designed
to make a bullet spin. For this reason, shotguns aren't as accurate at
longer ranges, especially compared to rifles. But shotguns loaded with
slug or with large pellets are accurate enough at ranges of 100 yards
or less (the probable range of the Maryland/Washington/Virginia murders
— and of more than 99 percent of violent-crime guns) to kill a person.
So a 100 percent perfect "ballistic fingerprinting" system would
likely encourage criminals to switch to shotguns (sawed-off shotguns are
almost as concealable as large handguns), but criminals would still have
an easy way to avoid detection.
An additional problem is the difficulty of making the comparisons. Nowadays,
bullets, fingerprints, and DNA are matched by taking the sample in question
and comparing it to a relatively small number of other samples —
sometimes just the DNA/fingerprints/bullets of one suspect, but, at most,
several possible suspects. The wider the sampling, the better the chances
of finding a match, but the greater the time and expense necessary to
do so. The more resources that are spent on data hunts, the fewer resources
that are available for other forms of criminal investigation.
For example, Maryland has mandatory sampling of all new handguns, at a
cost to handgun buyers of about $20 per gun (the cost to collect the sample).
For the state of Maryland, cost of the equipment and manpower to operate
the equipment amounts of $5,000 per handgun sold. The system has thus
far solved no crimes. Thus, so far, every dollar spent by Maryland for
the sampling scheme has been wasted money, money that could — in
a state currently suffering a budget crisis — have been spent on
more detectives or in other ways that really do solve crimes.
Perhaps one day, there will be a handgun owner in Maryland who will be
a lawful registered owner, who will not have intentionally or unintentionally
changed the barrel print, and who will commit some crime that gets solved
by the Maryland database. The crime might be an attempted murder, or it
might be illegally celebrating the new year by firing a gun in the air;
the cost of solving this crime might be approximately $500,000. Although
registered guns are used in an almost infinitesimal percentage of violent
gun crimes, if spending $500,000-per crime was actually the answer to
solving a quarter of the nation's annual gun crimes, the spending would
consume nation's entire criminal-justice budget. Wouldn't you rather have
a court and maybe a prison, too? And perhaps a few detectives and other
police officers?
But that cost figure is based on the hypothetical that the system would
work. In fact, ballistic markings are not even remotely as reliable as
fingerprints. Indeed, they are not even as reliable as tire tread analysis.
If barrel markings were reliable, then an analyst ought to be able, at
the least, to distinguish different types of guns. A tire-tread analyst
can usually tell what kind of tire made a tire print, even if he can't
be certain which individual tire made a mark.
As a bullet travels down a barrel, the rifling makes the bullet spin in
a spiral motion. This is done by putting lands (lines where the barrel
is narrower) and grooves (lines where the barrel is wider) in the barrel.
The number of lands and grooves, and their widths, vary depending on the
firearm model. The amount of spin put on the bullet also varies. For example,
Colt Sporters now generally spin 360 degrees every seven inches, and Ruger
Mini-14s every nine inches. The easy part of bullet analysis should be
determining which barrels might have made the markings on the bullet,
just as the easy part of tire-tread analysis is determining which models
of tires have the same tread as those found at a crime scene.
It is thus telling that the authorities in the D.C.-area murders, the
police are unwilling to exclude any of dozens of models of .223s from
consideration. The police even suggested that bullets might have come
from an AK-74 (an Eastern European firearm which is relatively rare in
the United States), even though the AK-74 fires bullet with different
dimensions from the .223.
One of the problems with any attempts at analysis is that bullets —
especially higher-rifle-velocity bullets — are frequently deformed
by whatever objects they strike. To use the DNA approach, imagine analyzing
a DNA sample with 50-80 percent of the letters missing. Or a partial fingerprint
where the majority of the print isn't there. The authorities in D.C. have
announced that two of the bullets are worthless even for matching to the
other bullets. The remaining ones appear not to be giving much information,
even of the broadest kind.
The best that can be said about the rest of the ballistic "fingerprinting"
— firing-pin and ejector marks — is that they're less unique
than barrel striations. Firing-pin marks are also subject to natural and
intentional alteration.
In short, so-called "ballistic fingerprinting" is vastly less
useful than real fingerprinting or DNA analysis as a crime-fighting tool.
It's far less useful than tire-tread analysis. By consuming immense resources
from the criminal-justice system, the gun-registration system would seriously
reduce criminal-justice effectiveness and cut the number of cops on the
street — as Canada's simpler gun-registration scheme already has.
From the viewpoint of the prohibition lobbies, however, the misnamed "ballistic-fingerprinting"
scheme does have advantages. The scheme amounts to partial gun registration
today (in any form that could be politically viable in the legislature),
setting the stage for more comprehensive gun registration in the future
(without which the scheme would be useless). Since "gun registration"
is a political loser almost everywhere, the gun-prohibition lobbies have
the opportunity to push for registration under a new, high-tech name.
And what is the purpose of gun registration? The former president of the
group currently known as the Brady Campaign, the late Nelson Shields,
explained registration's purpose in a 1976 New Yorker interview:
The first problem
is to slow down the number of handguns being produced and sold in this
country. The second problem is to get handguns registered. The final
problem is to make possession of all handguns and all handgun ammunition
— except for the military, police, licensed security guards, licensed
sporting clubs, and licensed gun collectors — totally illegal.
Gun registration
has been a very useful tool for gun confiscation in England, Australia,
New York City, California, and many other places. Criminals don't register
their guns, but many law-abiding citizens do, and when the government
makes ownership of the registered gun illegal, the gun-owner, knowing
that his gun is already on a government list, has little choice but to
surrender his gun to the government furnace. This is a pleasing result
for the gun prohibition groups, but if this is the public policy direction
for America, we at least ought to acknowledge what is being done, rather
than pretending that gun registration — cloaked in a high-tech euphemism
— is going to solve crimes.
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he Sniper has
reinvigorated gun-prohibition groups. Gun control is the answer for them,
of course, to a murder spree by someone using some kind of rifle or handgun
in a caliber of approximately .223. The prohibition lobbies and their
media dupes are calling the suspect .223 "high-powered," but
it's really about as low powered as a centerfire rifle gets. As a hunting
round, it's for varmints, not big game. While the Violence Policy Center
has been making a big deal about "sniper rifles" and "sniper
culture" (thereby denigrating the many decent people who serve as
snipers for the police or the military), the .223 caliber — if that's
what the shooter is using — is quite far from the long-range, high-power
type of rifle used by police and military snipers.
