knowing what gun fired the shot

[CSACANNONEER]

I know one person who works in balistics in Ventura County and one person who does the same for LA County. From what I've been told by them, yes in SOME instances, it is possible. Of course, there are many variables, including the condition of the bullet in question. A few easy examples come to mind. It's fairly easy to tell if a bullt has been fired from a factory Glock barrel or a Marlin .22lr barrel due to their unique rifling. It's also easy to tell if a cartridge has been fired from a MP5 type weapon by the burn marks on the case.

[Axewound]

how about extractor marks or firing pin impression. i know u cant get exact but things can get narrowed down.

[Jonathan Doe]

on the tube the cops say the gun that fired the shot..by make and model

Is this possable.?

I thought only the cal


.

Generally speaking, yes. If the shooter changed the barrel or characteristics of the firearm, then it will be difficult to say which gun.

Each manufacturers have certain specification of the broach that cuts the barrel, or certain way to forge the barrel (hammer forging or butten or whatever). Experts call it "general rifling characteristics". By measuring the diameter of the bullet, weigh it, counting the lands and grooves, twist direction and width measurements, the examiners refer to the FBI manual, which is about 3" thick, or on line manual, to confirm which firearm might have fired the bullet.

It is pretty accurate.

And don't trust everything that you see on TV, CSI series. It may not be very accurate as to what the real CSI does. However, forencis files, north Mission Road, detective files etc, are good program.

[dreyna14]

If somebody used a gun in a crime, they could easily change the specific identifying features of rifling impressions simply by damaging the barrel in such a way that the gun could still function, but the impressions change. A series of minor scratches in the grooves or lands. Hell, even going through a case of FMJ ammo could easily change the appearance of certain features making ballistic evidence unreliable.

[Mike's Custom]

My understanding of the ballistic fingerprinting programs in the other (2) states that have it, is that it has helped solve only 1 crime... and that could/would have been solved without that specific evidence generated by the ballistic fingerprinting program anyway. I think it was/is the Maryland State Police that wants to get rid of the program...

Actually, I think it was Mass. that had the balistic finger printing on all handguns sold. Last year it had been used 200 times with ZERO results. hte system cost something like 20 million and didn't work. That part has been suspended. According to the Feds balistic finger printing does not work and it is to easy to alter the parts. We all know that you can swap barrels or just buy a barrel, use it in a crime and then melt it down. Firing pins can be altered just from firing a number of rounds throught the gun after you use it in a crime or a little polishing and that to is altered. Lets face it, if I want to shoot someone and not leave behind anything but the bullet I would use a revolver. For a semi auto, I would use a Glock .40 and put in a .357 Sig barrel, do the shooting and then melt the .357 SIG barrel and reinstall the .40. I wouldn't even bother with the firing pin. If you really planned on doing something, just go to a gun show inanother state, buy a gun from a private party and leave it at the scene. Nope, balistic finger printing is a joke and so is bullet coding. Just to easy to get around if you want to and to easy to set someone up.

[Riodog]

Get a clue people. Everything in the firing sequence will leave an impression on either the bullet or the case. In a pistol, just changing the barrel will still get you jail time as the case imprints the breech face as well as the extractor, ejector and firing pin.
In a revolver, it's possible to tell which chamber the case was fired in.

Some ballistic techs are so good that they can tell what type and make of machine tooling was used to cut "what ever" on the weapon.
Rio

[DocSkinner]

If somebody used a gun in a crime, they could easily change the specific identifying features of rifling impressions simply by damaging the barrel in such a way that the gun could still function, but the impressions change. A series of minor scratches in the grooves or lands. Hell, even going through a case of FMJ ammo could easily change the appearance of certain features making ballistic evidence unreliable.

You can change them being able to tie it to a specific example of a gun by that, or even just by firing a lot of rounds between the two bullets that get checked, the accrued fouling can substantially change the MINUTE DETAILS of the rifling marks, but that doesn't change the specifics of how a manufacturer rifles their barrels - number of lands/grooves, type of groove cut, widths of cut, right or left hand spiral, etc which can all tie it to a specific gun - but not the specific example of that gun.

[redcliff]

Get a clue people. Everything in the firing sequence will leave an impression on either the bullet or the case. In a pistol, just changing the barrel will still get you jail time as the case imprints the breech face as well as the extractor, ejector and firing pin.
In a revolver, it's possible to tell which chamber the case was fired in.

Some ballistic techs are so good that they can tell what type and make of machine tooling was used to cut "what ever" on the weapon.
Rio

It's a little more difficult I would imagine on revolvers if the bad guy didn't stand over the body and do a reload dumping the cases.

I'd think the ultimate hard to trace weapon is a double barrel shotgun. No rifling and no case left behind, just the wad.

[dreyna14]

You can change them being able to tie it to a specific example of a gun by that, or even just by firing a lot of rounds between the two bullets that get checked, the accrued fouling can substantially change the MINUTE DETAILS of the rifling marks, but that doesn't change the specifics of how a manufacturer rifles their barrels - number of lands/grooves, type of groove cut, widths of cut, right or left hand spiral, etc which can all tie it to a specific gun - but not the specific example of that gun.

And if that gun is even remotely popular, there is plenty of reasonable doubt as to the identity of the actual weapon used.

[Kid Stanislaus]

Depends upon the specific crime lab BUT yes they can tell you just about everything except for the serial number. (that might nbe in the future).
Rio

Don't make me puke up my Christmas dinner!!!

[Kid Stanislaus]

If somebody used a gun in a crime, they could easily change the specific identifying features of rifling impressions simply by damaging the barrel in such a way that the gun could still function, but the impressions change. A series of minor scratches in the grooves or lands. Hell, even going through a case of FMJ ammo could easily change the appearance of certain features making ballistic evidence unreliable.

I'm think'n fire lapping would do the job too.

[Mike's Custom]

I'm think'n fire lapping would do the job too.

Firelapping will sure do it. But that is not really needed. You swap a barrel and then junk it. A pass on the bolt/breach face with some lapping compound or even 1200 grit paper or most anything abrasive wil change that. The firing pin is next and just shooting more rounds will alter that or a little polishing will certainly change that. This is something most people can do in minutes. A wire brush will also change things. CSI labs can find things only if you leave it. A easy thing to do is just shoot and drop if you have left no finger prints or paper trail. No paper trail is harder to do but not impossible.

[SkatinJJ]

Actually, I think it was Mass. that had the balistic finger printing on all handguns sold. Last year it had been used 200 times with ZERO results. hte system cost something like 20 million and didn't work. That part has been suspended. ....

http://www.saami.org/news/viewPR.cfm?PRloc=share/PR/&PR=100208_SAAMI.cfm

SAAMI website had this:

October 2, 2008

For more information contact:

Ted Novin
203-426-1320

Sporting Arms Industry Statement on
Failures of Ballistic Imaging Database

The failure of the New York and Maryland ballistic imaging database systems to solve any crimes in their nearly eight years of existence was predictable. In 2001, California wisely rejected setting up its own ballistics imaging system because research, including by the California Department of Justice, proved that a database of lawfully purchased firearms (that are rarely ever used in crimes) would not be an effective law enforcement tool. Another study released earlier this year by the National Research Council confirmed the findings and advised against setting up a national ballistics imaging system. New York and Maryland have wasted millions of taxpayer dollars on systems doomed to fail.

not

As the failures of ballistic imaging are becoming known, some gun control advocates that had initially supported mandating ballistic imaging databases are now promoting a new technology, called firearms microstamping.
Firearms Microstamping is the patented process that laser engraves the firearm's make, model and serial number on the tip of the gun's firing pin so that, in theory, it imprints the information on discharged cartridge cases.
Microstamping is a nascent technology that numerous independent studies , including by the NRC, University of California at Davis and renowned forensic scientist Professor George Krivosta, have proven to be unreliable and easily defeated in mere seconds using common household tools. Furthermore, microstamping can be simply evaded by criminals by switching out microstamped parts on a firearm for unmarked spare parts. In fact, yesterday Washington, D.C. Police Chief Cathy Lanier joined the firearms industry in calling for further research into microstamping prior to any legislative mandate.
While the firearms industry welcomes further independent study of either technology, SAAMI supports allocating taxpayer dollars to proven means of crime reduction such as more police officers and more prosecutors.

SAAMI was created in 1926 at the request of the U.S. government to create standards related to safety and reliability. Technical excellence is always our goal and safety is always the prerequisite. SAAMI supports science-based solutions to the many issues related to firearms, ammunition and components. Information and a description of the function of each committee is available by visiting the SAAMI Web site at www.saami.org.

[DocSkinner]

And if that gun is even remotely popular, there is plenty of reasonable doubt as to the identity of the actual weapon used.

yep - but you also have to remember that California is one of the states that allows admission/conviction on circumstantial evidence....

[DocSkinner]

Firelapping will sure do it. But that is not really needed. You swap a barrel and then junk it. A pass on the bolt/breach face with some lapping compound or even 1200 grit paper or most anything abrasive wil change that. The firing pin is next and just shooting more rounds will alter that or a little polishing will certainly change that. This is something most people can do in minutes. A wire brush will also change things. CSI labs can find things only if you leave it. A easy thing to do is just shoot and drop if you have left no finger prints or paper trail. No paper trail is harder to do but not impossible.

with duct tape on the grips - just like in the old gangster flicks!

devils advocate here, but if they suspect you and check your gun and see recent "polishing" of bearing surfaces, is that kinda like shaving a beard right after a crime committed with the beard? Not sure what the term is - basically a guilty conscience act, or something like that?