Forensic ballistics question

http://www.amazon.com/dp/1582974748/?tag=absowrit-20

Pretty standard tool in the US: http://www.forensictechnology.com/ibistrax

-cb

Well, in the 70's, .45 Automatic Colt Pistol (ACP) ammo was pretty much limited to full metal jacket (FMJ) round nose (what the military calls 'ball ammo'), lead round nose (RN), along with lead hollowpoints (HP) and partially jacketed hollowpoints (JHP). The Colt Government .45 ACP pistols of that vintage had to be 'tuned' (modified by an expert) to reliably feed the HPs and JHPs. Not many other pistols shot the .45ACP in that era.

Then there's .45 Long Colt, a rimmed cartridge for the famous Peacemaker single-action revolvers (as well as double-action revolvers from Colt and S&W).

The bullets can be differentiated by weight. The most common bullet for the .45 ACP weighs 230 grains, while the most common .45 Long Colt load used a 255 grain bullet. There's a slight difference in bullet diameter too.

A 230 gr lead hollowpoint would date the ammo to the '80's or earlier, but not tell you anything about the pistol used to fire it as lots of mfrs now make weapons in that caliber. Jacketed hollowpoints would be from a later era. And the 'flying ashtray' type hollowpoints only came into usage in the last twenty years or so.

So which one do you want?

Stan

Stan,

A bit off subject, but I grew up in Paterson, NJ, and had been told that the Colt .45 Peacemaker was invented by Samuel Colt there. Yet, I read that Colt moved his operations to Connecticut in the early 1800's. If so, it must have been invented in Connecticut. Who's right?

to AW! I'll be whisking you away to the Experts forum, where you'll get wider viewership for your question (not that you need it with Stan on the scene!)... hang on to your hats!

grizzletoad1 said:

Stan,

A bit off subject, but I grew up in Paterson, NJ, and had been told that the Colt .45 Peacemaker was invented by Samuel Colt there. Yet, I read that Colt moved his operations to Connecticut in the early 1800's. If so, it must have been invented in Connecticut. Who's right?

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Wiki says Colt's first factory was in Paterson NJ, building the Paterson Colt, a percussion revolver with folding trigger. Then he went bankrupt and closed the plant in 1843. Full article here.

Stan

In New Hampshire, bodies are sent the Chief Medical Examiner's lab, which I believe is located at Concord Hospital. There the bullet would be extracted from the body, and placed in a bag for transfer to the forensic labs on Hazen Drive in Concord. In the case of a gunshot, I believe that the appropriate person from the lab will be at the autopsy. This is where you start determining angle of fire, so on and so forth.

The question for the forensic lab is whether they have a probable weapon. If they have the weapon, all they need to do is confirm that the bullets match, which is a relatively simple process. Broadly speaking, if the weapon isn't available, the New Hampshire lab can give some parameters on the weapon, age of the alloy used in the bullet, and some other information.

But if the bullet baffles the State lab, it is then sent to the FBI labs for further analysis. At a certain point, if the bullet is in good enough condition, then you can narrow it down to just a few possible weapons that might have fired it.

Question is what is the present level of expertise at the State's lab, and this varies a bit as different people hold down the job.

Definitely the lab person would identify an unusual bullet. What you want to ask the gun experts here is what type of weapon and bullet would be distinct to the time period that you want.

Best of luck,

Jim Clark-Dawe

If the bullet was a lead round nose or hollowpoint, without a copper jacket, it would likely be from a batch mfd in the 70's or earlier. Lead also 'blooms', develops a whitish outer layer. There may be some way to determine the age of a bullet from that. I have some .38 S&W ammo made in the '30's that has developed significant blooming. It shoots just fine.

There would be no way to determine the age of the weapon from the fired bullet. In fact, the only markings on the bullet are rifling marks. Some mfrs such as Glock, H&K, Kahr, and others use polygonally rifled barrels. Those leave a different kind of mark on the bullet.

So a forensics dude could say a bullet came from a Glock barrel, or an H&K barrel, or a 1911 barrel. That's about it. There's no way to tell the age of the barrel. 1911 barrels in particular haven't changed in a hundred years. 1911-2011, get it?

But if your guys found a 230 gr lead round nose with significant blooming, there's a decent probability it was fired from a WWII-era Colt Government Model 1911A1. Anything newer would likely have newer bullet design ammo.

Stan

Stan:

I'm wondering if the "blooming" leaves a trace as a bullet as it passes through an object. For instance, if you fired through a piece of wood, would it leave this white layer? And if that's the case, I'd guess it would also leave a white powder in a human body as it passed through soft tissue.

Next question is how much "old" ammunition is there out there. New Hampshire runs in the double digits (less than a hundred) murders per year, so something that is common in LA isn't here. Last year we had ten, with only four by firearms. (Poster is from NH, but I don't know if his story is set there.)

I'm thinking if old ammo is relatively rare, and murders are rare, this blooming is going to be very unusual and very distinct to anybody in New Hampshire.

Best of luck,

Jim Clark-Dawe

jclarkdawe said:

Stan:

I'm wondering if the "blooming" leaves a trace as a bullet as it passes through an object. For instance, if you fired through a piece of wood, would it leave this white layer? And if that's the case, I'd guess it would also leave a white powder in a human body as it passed through soft tissue.

Next question is how much "old" ammunition is there out there. New Hampshire runs in the double digits (less than a hundred) murders per year, so something that is common in LA isn't here. Last year we had ten, with only four by firearms. (Poster is from NH, but I don't know if his story is set there.)

I'm thinking if old ammo is relatively rare, and murders are rare, this blooming is going to be very unusual and very distinct to anybody in New Hampshire.

Best of luck,

Jim Clark-Dawe

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The bloom is lead oxide, a white powdery material. I can rub it off with my fingers. It should leave a trace in the bullet track.

As for availability of old ammo, like I said I have some from the '30s. About 200 rounds of .38 (not .38 Special). It's not particularly rare, but not plentiful either. In fact, there's a few sources for it on the internet.

I'm sure there's a lot more WWII-era .45 ACP ammo out there. Millions of rounds ended up in govt warehouses and was sold as surplus when DoD went to 9mm.

Stan

Is it still good after all that time? I guess what I'm asking is, is there an expiration date on ammo?

grizzletoad1 said:

Is it still good after all that time? I guess what I'm asking is, is there an expiration date on ammo?

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It still goes bang. But I wouldn't bet my life on it going bang every time. But then I wouldn't depend on a .38 S&W even if it had new ammo in it. It's a pretty weak load.

Some military ammo is sealed with shellac to prevent moisture degrading the propellant. I've seen sealed 7.62x39 that came in rotted wooden crates, packed in cotton bandoliers that were disintegrating. But it shot just fine.

Stored properly in a sealed ammo box, with a desiccant, the shelf life of non-corrosive primed ammo is indefinite. No, there's no expiration date.

Stan

chuckgalle said:

Thanks Stan. You've been a big help. Lemme make sure I understand.
If my victim was killed in 2001 with a .45 that had been stolen with ammo from an NG Armory in say, '73, ballistics would reveal that the slug was that old.

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Not definitively, but with a high degree of confidence. In addition to the type of bullet, and blooming (if present), it may be possible to differentiate the lead alloys used in the 70's from those used in factory ammo today. I don't know enough about the metallurgy to comment on that.

But it wouldn't tell them anything about the weapon other than it was a 1911-type pistol.

Stan

It may be worth mentioning that older style bullets can be cast. Also, old bullets could also be yanked out of old cartridges and placed in newer brass--or, set into older brass with new powder and primers--if someone wanted to cause confusion (hope I didn't).

chuckgalle said:

Yeah, that's fine. Thanks. They'll identify the weapon after it's found. I mostly just want to have the bullet suggest it's own age, to set my readers mind to wondering. 'Preciate the help.

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Could the casing be found? The casings usually have markings that tell you when it was made and by whom.

With regards to the age of the weapon, a forensic tech can tell you if the barrel was worn, indicating that it had fired many rounds.

The same goes for the casing, the weapon may leave marks that indicate type and model, and how worn it is.