Topic: Caliber, cartridge case, GSR and other questions (Read 34909 times)

tww1017 · « **on:** October 19, 2011, 11:20:16 PM »

MC comes down the stairs with handgun and surprises BG. Brief struggle as several wild shots are fired.

BG raises hand to push gun away. Barrel is against BG's palm at base of finger and MC fires.

BG pulls back and MC fires another shot that strikes BG in head.

Questions:

1. What caliber would be strong enough to cause the finger to be separated from the hand by the blast?

2. What caliber would be strong enough for a shot to exit the head? How close would such a shot have to be?

3. General question about GSR: how big an area is affected by a revolver versus a semiautomatic?

4. This shooting takes place in an interior hallway of MC's home. How strong will gunshot smell still be in 1/2 hour? 1 hour? How long until it disappears? Or is that only possible with forced ventilation?

5. Likewise, how strong would the "meaty" odor of a dead body be after 1/2 hour? One hour? Hard to answer that, but how fast does such odor start to fill the hallway when the home is at, say, 72 degrees?

6. After evidence is collected at a crime scene, what is the typical time required to examine cartridge cases for ejector markings? What about for markings on the bullet itself?

In advance, I thank whoever takes time to answer my questions.

Thank you,
Terry

tww1017 · « **Reply #1 on:** October 20, 2011, 09:04:53 AM »

One other question: is the damage of a bullet found in the interior wall structure of a house after passing through a victim's flesh and or bone, sheetrock, and found lodged in the wood framework too great to provide enough detail to link it to a specific weapon?

Supposing it strikes a nail in the framing?

I know it depends on many factors, but I'm looking for some general remarks from those of you who know much more than I as to what is realistic in such circumstances.

Bob Mueller · « **Reply #2 on:** October 20, 2011, 01:21:07 PM »

Welcome aboard! Let's see what we can do here.

Quote from: tww1017 on October 19, 2011, 11:20:16 PM

MC comes down the stairs with handgun and surprises BG. Brief struggle as several wild shots are fired.

BG raises hand to push gun away. Barrel is against BG's palm at base of finger and MC fires.

BG pulls back and MC fires another shot that strikes BG in head.

Questions:

1. What caliber would be strong enough to cause the finger to be separated from the hand by the blast?

Depends a bit. At that range (contact), a .357 magnum would do it, as would anything larger. However, if the hand is actually pushing against the barrel (and slide) of a semi-auto, the gun could malfunction. If the slide is even 1/8" out of battery (not fully forward), the auto won't fire.

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2. What caliber would be strong enough for a shot to exit the head? How close would such a shot have to be?

At contact range, a .22 through the eye might exit. Just about anything larger would also exit, up to a couple of feet away.

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3. General question about GSR: how big an area is affected by a revolver versus a semiautomatic?

I can't speak to size of the area exactly, but a revolver will throw more residue due to the very slight gap between the front edge of the cylinder and the breech of the barrel.

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4. This shooting takes place in an interior hallway of MC's home. How strong will gunshot smell still be in 1/2 hour? 1 hour? How long until it disappears? Or is that only possible with forced ventilation?

For someone coming in from outside, I'd guess the smell would be pretty noticeable for the first half hour, but that's only a guess.

I'll pass on 5 and 6 for other more knowledgeable people.

linda · « **Reply #3 on:** October 20, 2011, 06:25:27 PM »

Terry,

Bob did a great job of answering your first questions. I'm not certain about #6 because the speed in which they're checked is dependent on the case; a homicide with an active suspect and seized weapon gets precedence over almost anything else, etc.

On #5, there's a difference in the smell depending on the wounds. Am I correct in assuming that, based on your questions about the shooting, that you will have blood and brain matter at the scene? While I can't answer the time period, I know that there is a sharply different smell between a dead body and a dead body with open wounds, blood, brain matter, organ matter and so on involved.

Linda

Old Bill · « **Reply #4 on:** October 21, 2011, 10:23:37 AM »

Terry,

Good but difficult questions and Bob and Linda have given you good answers.

There are a lot of variances that occur with gunshots and crime scenes. Bullets, especially, do crazy things. This is unfortunate for the investigator trying to piece together the scene but great for writers cause we can get away with lots of weird stuff.

Most ballistics are performed on deformed bullets depending on what they have hit/penetrated. Most came to the lab looking like mushrooms or their jackets have peeled off. These types are USUALLY identifiable. The land and groove striations are near the base of the bullet and may be intact. .22s are notorious for deforming or splitting into pieces and their size doesn't help either. Obviously a full copper/metal jacketed bullet will fair the best even after penetrating several materials. Some of the man-stoppers on the market today are made to release most/all of their energy inside the body and may not necessarily exit, even through the head and while they tend to break up, their jackets may still yield striations good enough to make an ID.

If you live in or near a large city, they probably have a ballistics examiner in the police department or lab. See if you can make an appointment to discuss these things with him/her. It will be interesting and I'll bet most are eager to share their experiences and expertise.

Good luck.

Old Bill

tww1017 · « **Reply #5 on:** October 21, 2011, 06:27:59 PM »

My thanks to all of you for replying here.

Old Bill, your advice to talk to a local crime lab makes great sense. We do have a crime lab in the county where I live (Charlotte/Mecklenburg, NC).

Do you think they would be open to talking to me?

All I can do is ask.

Again, thanks to all for replying.

Terry

Old Bill · « **Reply #6 on:** October 22, 2011, 08:08:30 PM »

I'm willing to bet the lab boys will talk with you. Some tips: be professional; go through channels with letter of intro to the lab director; if you're published, consider offering a sample or if not, maybe a draft of a section they could review for you to see if you're on the right track; offer to acknowledge either the lab or some helpful person in the book; and remember this saying: what you see, what you hear, when you leave, leave it here.

Good luck. Let us know how you make out.

Old Bill