I've used it a lot, lately.
Cheers my FRiend...beware of the incoming, low-flying..
Posted on 05/02/2016 2:25:05 PM PDT by Chasaway
I need some general firearms/ballistics information.
I'm working on a criminal defense case. The defendant is accused by the state of shooting his girlfriend in the back of the head with an AR-15 at 10 feet...using a .223 round.
The defendant is a real scumbag and knows he's going to the pen over this. BUT, he claims he accidentally discharged the gun, it caromed off of a linoleum-covered concrete floor and then struck her. It all occurred in a very small kitchen.
My working hypothesis is that this WAS an accidental shooting and that the bullet DID ricochet off of the floor. That means that the defendant couldn't have MEANT to shoot her, because there is no way to accurately predict, ad hoc, the performance of a bullet after caroming off of a concrete floor.
Also, if he HAD shot her directly from 10 feet, I wouldn't expect the round to fragment and stay in her brain pan and I would expect to see some other residue from the round on her clothes or in her hair, etc.
I've used it a lot, lately.
Cheers my FRiend...beware of the incoming, low-flying..
Yes there is a reason they call it pink mist.
I know exactly what I’m doing. Do us a both a favor and re-read my original post.
It’ll save some time. I won’t have to spend as much time calibrating you.
Thanks. That fits my thoughts...and the evidence.
I’d still like to hear if anyone has any direction on what should have been found on the victim/shootee regarding gunfire residue if it WAS a straight shot.
Absence of such would indicate it is not.
C
Sorry, I have a real hard time trying to come up with reasons to help a guy who “had an accident” with an AR-15. Rule number 1, every gun is loaded all the time, Rule number 2, never put your finger on the trigger unless you plan to shoot. There’s just no reason to have an accident with a gun.
From my original post.
Would it be helpful to you if I wrote it differently next time?
I agree with you.
But stupidity doesn’t equal murder, by itself.
It’s definitely criminal. But not murder, which includes an element of intent.
And if you did something stupid, wouldn’t you want as much help as you could get to show it wasn’t purposeful?
Or would you hold the same view; refusing any assistance because you’d done something you knew better than to do?
Not to worry, every 4 years I don’t discuss politics, and never, ever go in to the religion forum without a note from my mother.
With a prison term on the line, I would take a fragment of the actual floor and try to recreate the ricochet scenario in a lab.
I’d suggest a reenactment in a vacant house with similar floor and temporary wallboard with backing. It would not be expensive to find a vacant house in which to conduct such a test with a ballistics expert present, holding the rifle at the same angle and using the same ammunition.
Then you'd be looking for the absence of explosive head splatter.
See the image at the link provided by Tijeras_Slim at post #85 above. That's what the victim should look like, roughly. If there's not that level of damage to the head, it wasn't a straight shot.
Also, this is not rocket science - .223 is basically our military rifle caliber. Expert witnesses on wound severity therefore would not be hard to come by.
Last time I was on a religious thread I pretended I was a Buddhist or a Hindu and rejected my baptism [which was by fire]
If the prosecutor on your case were to happen to run across this thread, he'd recognize the case instantly. And you'd lose the one real advantage that a defendant has in a criminal case-- surprise. The prosecutor would know what the defense is going to be and would be prepared for it.
Our investigator is urged to go very cautiously here.
There are two MIL STD rounds for 5.56x45mm: M193 and M855 (now M855A). M193 fired a 55gr bullet with a gilding metal jacket and a lead core to a muzzle velocity of 3280 ft/sec. It is no longer standard (but equivalents are widely available on the commercial market). M855 has a gilding metal jacket over a hardened penetrator with lead filler (original configuration) and fires to a muzzle velocity of 3100 ft/sec.
Some decades back, military firearm authority Peter J. Kokalis stated in print that the M193 loading was more lethal than either 30M1 (US 30-06 WWII: 153gr jacketed, 2750 ft/sec) or 7.62 NATO (147gr jacketed, 2740 ft/sec), within ranges of 100m. Out to that distance, the M193 projectile retained sufficient velocity to fragment on hitting a human body (no, he did not say where). Beyond that, it punched through - like the larger, more stable 30 cal bullets did at lesser ranges. By contrast, M855 was designed to give longer effective range and afford better penetration at long ranges - it will out-penetrate that 30M1 bullet at 850m.
I’ve witnessed 22 cal soft point bullets punch clean through the web (support portion) of a railroad rail. Fired from a 22-250 at some 3500 ft/sec; range was under 50 ft. We did not recover any spent bullets.
Penetration is thus probabilistic (not much help for our investigator, I know), and highly dependent on impact velocity, tissue (bone, skin, muscle etc) density, angle of incidence, etc. Humans vary a lot: not even a side-by-side comparison of bullet wounds can tell us much.
One hears that the mere discharge of a firearm in the general direction of another person constitutes intent. Not sure how well this legal ploy works.
5.56mm MIL STD ammunition is identical in exterior dimensions to commercial 223 Remington. The warnings from manufacturers not to fire 5.56mm in a 223 stem from the difference between military and commercial chamber dimensions. Military chambers are cut larger, chiefly to improve feed reliability in full-auto arms. The leade is also longer. Military chambers also need more generous tolerances, to handle ammunition of allied origin. Some commercial chambers can be very tight; this is usually done to enhance accuracy (in bolt action arms) but ups pressure. The warning applies chiefly to M855, which can produce higher mean pressures.
I am no Expert, nor do I claim to be at all ... ideas and observations from sources including TV...
First thing you might want to do is Cut that piece of Floor up. It may be worth more than all the information that you are asking about. If the floor was “First” contact of the Projectile, what is it’s make-up? If it is a Conglomerate what was the actual material of the initial deflection?
When you are talking 2,800 to 3,250 ft per second there is no real measurable angular distance at 10 ft (basically 5 ft if you halve the distance)
The height of the barrel, the height of impact and angles of initial/post trajectory. (This is basic Math) What did the projectile hit? (Concrete, as in Cement or a piece of Aggregate in the Concrete), that Aggregates Shape, Hardness and Depth beneath the Linoleum as well as covering Cement would have more influence on the projectile than distance.. etc.
It can be proved as possible or impossible without even knowing exact velocity, velocity in that short of a distance even if halved by a 90 deg change in direction is still a avg minimum of 1400 fps so you need the weight of what was left of the projectile, was any of the projectile left in the floor, shape of the projectile (prior to entry) entry point (as in flesh or bone) of the victim and shape of projectile at post.
If it was a CSI TV show, It would start with the floor, then the angles then the projectile and fill in the middle with what was determined to be possible. Then the Autopsy, Testimony and other Evidence... it is a puzzle
I AM ONLY SUBMITTING THIS TO GIVE YOU IDEAS, I REPEAT I AM NOT AN EXPERT AT ANYTHING MENTIONED ABOVE.
I wish you luck and if you just need someone to think about alt what ifs and ideas just ask.
Agreed. And it isn’t just the accident angle. This guy could have dumped a round in the floor which spattered harmlessly, just to scare his girl before getting really pissed and hitting her with an old round that almost didn’t fire, or even punching her through something she tried to hide behind, like a chair or other obstacle, which he disposed of prior to the cops getting there.
My guess is the prosecutor knows more than is presented here. I mean he is a low rent scumbag thug (presumably with a rap sheet, if that is how his lawyer describes him) with an AR. How’d he get the AR? Was it stolen? And he got a girl killed? Was there history with the girl?
Assholes like this fuck up RKBA for the rest of us, even if they didn’t affirmatively kill an innocent. Add in that, and I say lock the guy up.
And yes, I know you asked for help, but others have the prerogative to make the case this guy doesn’t deserve it, absent a lot more intel.
And the big question, why is a scumbag (as described by his lawyer) in a small kitchen with his girl, with a loaded safety-off AR with his finger on the trigger in the first place?
Maybe I missed it being brought up, but I think it was only mentioned by others as checking the floor for bullet material evidence. Any chance concrete or linoleum fragments/residue was looked for in the deceased under a similar material transport/deposit premise?
It starts with the distance the weapon was from the victim and if the victim was standing, basic geometry. The closer the victim was the sharper the entry angle would be if the bullet came from the floor. If the bullet entered at a very numerically low angle (assume 0 degrees being straight in) say 10 degrees or less he was shooting at her and not the floor. If the bullet came from the floor and the victim was relatively close (like in the same room) you would see an angle of 30 degrees or more. Rarely do you see a bullet ricochet at a sharp angle they skip like a rock thrown on a pond. At sharper angles they tend to fragment and you get shrapnel effect and not one projectile.
If the bullet entered from a low angle (the floor) the exit blood splatter would be high as well and you would see blood high on walls or ceiling.
Bfl
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