Erasing ballistic fingerprints (shell casing method)


August 16, 2004, 11:47 AM
We all know that ballistic fingerprinting, the one with the shell casing, is bull, yet NY seems to be the only place still pushing for its expansion. Common sense doesn't appear to be doing any good, nor does the millions lost on this waste of time. So I have considered another approach.

I am considering adding a page to a NYC rkba site that I am working on that will give detailed descriptions on how to erase ballistic fingerprints from a new firearm. I figure it would be a good slap in the face of ignorant politicians. I have read that you can just scratch it off or even fire the weapon with bullets that are coated with a small amount of toothpaste. Not being a gunsmith I would like to know if anyone out there has a more concrete step by step preocess that would work to erase the fingerprints.

If so please let me know.

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August 16, 2004, 11:55 AM
Altering a gun for such purposes is probably illegal. What NY has found is that it's a farce. The cases included with the gun are not always the ones fired from that gun etc etc. But it makes the antis very happy.

August 16, 2004, 12:04 PM
I can see the point of your project, but I think it could blow up badly in your face.

I think that the anti-gunners will accuse you of providing criminals with the means of getting away with murder.

August 16, 2004, 12:18 PM
ALtering the fingerprint would in and of itself be used as evidence that someone tried to actively conceal something about a firearm and would look BAD to a jury. As to the illegal part, I can't say although I do know that it is illegal to remove the serial #.

If you are overly worried about the throretical fingerprint, just shoot the gun a little and it will change on its own. Trying to modify it would probably damage the accuracy potential and possibly make it non functional.

R.H. Lee
August 16, 2004, 12:25 PM
Since I don't know what I'm talking about, I'll give an opinion. If the firearm is a semi auto, changing the firing pin, extractor and ejector will go a long way toward altering the "ballistic fingerprint". You will still have any marks left on the case by the chamber, if they can even be matched. However, unless you change the barrel (which would take care of any chamber mark concerns) don't you still have the lands and grooves marks on the bullet that will match the original sample?

And what are we trying to accomplish anyway?

Harry Tuttle
August 16, 2004, 12:28 PM
nothing wrong with a buff and polish of the firing pin, bolt face, and chamber

why dremel makes a fine soft buffing bit and Crest is a great rouge

August 16, 2004, 12:36 PM
If you ever need to diguise the casing, use a revolver and then drop a dozen empty cases on the ground that you found at the range. You can even be real creative and shoot 125gr .38 Specials and drop 9mm brass on the ground.

Of course they're always muzzleloaders.

August 16, 2004, 12:46 PM
you do it naturally as you fire. The plan is just show how stupid it all is by showing how easy it is to erase them. Basically I want to be able to say "expand the database as much as you want. We're telling everyone how to eliminate the prints anyway in protest."

I know u have to buff anything that touches the round. So do you use a Dremel buffing attachment with toothpaste? Is that how to get rid of them?

August 16, 2004, 12:54 PM
Careful....NJ barely dodged the bullet on a "loophole closure".

Anticipating success on a ballistics database, (that thankfully never passed) the gun bigots proposed truly heinous legislation aimed at closing the "altered print" loophole.

Basically, they wanted to criminalize people from replacing any parts that could affect the print, posessing any parts that could replace the print, etc.

The only exceptions was work done by licensed gunsmiths, who had to submit the firearm to the state cops for the purpose of taking another print shell for the database. The legislation had no limit on the amount of time the state cops could keep the firearm, and as we all know, the NJSP has lots of practice sitting on things even if there is a statute mandated timelimit.

Cool Hand Luke 22:36
August 16, 2004, 12:57 PM
If you ever need to diguise the casing, use a revolver and then drop a dozen empty cases on the ground that you found at the range. You can even be real creative and shoot 125gr .38 Specials and drop 9mm brass on the ground.

That and fire 6 different sized bullets from a Medusa revolver.

R.H. Lee
August 16, 2004, 01:03 PM
Basically, they wanted to criminalize people from replacing any parts that could affect the print, posessing any parts that could replace the print, etc.

HAHAHAHA! Yeah, that'll be happenin'...................Let 'em want

Harry Tuttle
August 16, 2004, 02:08 PM
so how would they stop 4 guys
with 4, glock 17s
that want to trade parts?

serialize every part of the ballistic system?

shooting steel cased ammo would alter the fingerprinting

so would all extensive shoot & paste firelapping break in routines

August 16, 2004, 02:17 PM
I can understand the point, I think, but this could be construed as instructions on how to tamper with evidence, if a person where to read between the lines.:uhoh:

August 16, 2004, 02:20 PM
Don't forget about the area around the firing pin hole. When I shoot .357 Magnum, the tool marks are very prominantly imbedded it the primer. With .38 spl, however, they aren't noticable.

I don't think he's asking how to do it because he wants to do it. It seems like he merely wants to post the information. Considering the Poor Man's James Bond books, et al, I don't see why he couldn't post it.

The reason he shouldn't post is is, as was mentioned, NJ dodged a bullet because the antis wanted to close the "loophole" with a law that would have been a real disaster.

By the way, seems to me that balistic fingerprinting is an excellent reason to allow the AWB to sunset; without a semi-auto blowing cases all over the country side, there is a very great possibility that there will be no cases left behind. Then use some kind of frangible bullet and the whole thing goes down the tubes.

August 16, 2004, 03:11 PM
It is not uncommon to polish the breach face and feed ramp of semi-autos to improve feeding. This will change some of the marks on the case particularly on the primer and rear of the case and marks on the nose of the bullet that come from the feed ramp. Also you can get fire lapping kits (goolge <fire lapping kit>) that contain very soft lead bullets, several grades of very fine abarsives and instructions. These kits will allow you to remove almost all of the tool marks from the bore and also make the bore diameter more uniform. This results in reduced group sizes. But also significantly alters (eliminates) the marks made by the bore on the bullet. So what is left? How about polishing the walls of the chamber, the tip of the firing pin, the face of the ejector and the claw of the extractor. Other than the fire lapping operation none of these takes more than a few minutes to do.

I have also read that some manufacters now make barrels that are so uniform that it is almost imposibile to tell these apart when examining the makes left by the bore in new guns. This is particularly true for barrels that have "cold forged" bores. In the case of guns with these barrels the differences in the marks left by the bore will INCREASE as the guns are fired, cleaned and used.

August 16, 2004, 03:50 PM
NO! NO! NO! :banghead:

There is no such thing as a Ballistic FINGERPRINT! What the Anti's are talking about is properly called a Ballistic SNAPSHOT!

This term more appropriately says what is occuring with these tests and requirements. Once you have taken your snapshot the world changes through normal use and activities. The only way a SNAPSHOT has any validity is if you can test the weapon immediately or as close to that as possible.

Please do not encourage Anti's by using THEIR inappropriate language!

Molon Labe
August 16, 2004, 05:26 PM
Altering a gun for such purposes is probably illegal.Show me the law.

August 16, 2004, 07:07 PM
I used to think the "9mm in a revolver" trick would work, but it is not foolproof. The bullet will get scraped as it leaps from the cylinder to the barrel. This can be identified and point the investigtors in the right direction.

Most of the ballistic snapshot stuff revolves around the primer with imprints of the breech face and counting lands and grooves and the twist rate on the bullet. Certain manufacturers use certain twists and grooves which can help narrow the search for a weapon.

The big danger to a mass "fingerprint" database is in overwhelming the investigators. Right now, most places just have bullets and casings used in criminal activity in their system. A LOT of the work is done by hand. There is no "computer matching" system like what they show on TV. If your system (they are not linked nationwide) is flooded with legal purchased weapons that have never been involved in a crime, you still have to compare them.

For example, say a robber has been using a handgun in a string of bank robberies. He finally shoots someone, leaving a case and a recovered bullet. The ballistics guys can examine the case and bullet. Mostly likely they can narrow it down to a specific manufacture or model, say the Glock 9mm. Then they can go through their system to see if there is a match (perhaps to the gas station robberies the bank shooter started on 5 years ago). If he has only 50 9mm Glocks to match (all used locally in a crime), he can be done in a week or so. But if he has 50,000 Glcoks to match (every glock sold in that state), then it will take a team MONTHS to match, something no one can afford, not to mention the cost of inserting cases into the database in the first place.

Face it, "ballistic fingerprinting", just like gun locks, ammo restrictions, registration, training requirements, and all that are just tools to make gun ownership more expensive or more difficult, they have little or nothing to do with lowering crime or safety.

PAC 762
August 16, 2004, 08:36 PM
I was always under the impression that stainless steel bore brushes were so popular due to potential uses other than cleaning.... ;)

cracked butt
August 16, 2004, 09:54 PM
Just shot the gun alot and the 'ballistic fingerprints' will deteriorate.

August 17, 2004, 12:03 AM
I wonder how much using shell casings that have be reloaded and fired multiple times, from multiple guns, would screw with someone trying to make a ballistics match.

"Look here Bob, the distinctive markings from a Glock."

"Yeah, Jim, but this here's for sure the mark left by a Colt 1911 extractor"

"Um, guys? The firing pin mark is from a Ruger P90"

August 17, 2004, 01:06 PM
Piddle on messing with the case. Lose it altogether. I'm not sure if the VoereVEC ( is being actively imported but I'd kinda like to have one.

The Voere also has the advantage of giving the VPC a case of the vapors as shown in this vintage page ( , but is also shown on Feinstein's web site as a "good" gun here ( thus assuring additional confusion amongst the banners.

'Course the Voere is just an expensive way of accomplishing what anyone could do by simply picking up his brass. They don't seem to see it that way, though.

August 17, 2004, 01:34 PM
"9mm in a revolver" trick

I guess it might be more interesting if a criminal went to a police range, gathered up a pile of brass, then went about his mischief, dropping police issued brass like a little "Johnny Appleseed of Confusion" wherever he went.

Again, those that are on a "ballistic database" agenda tend not to believe a criminal would think of such a thing. My friends employed by NY corrections would beg to differ. Not only would the positive use of such a system be dubious, its potential for misuse has hit nobody's radar.

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