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pfch1977
January 5, 2008, 01:40 AM
I always see people debating the issue of "what if" their bullet goes through a wall.

I dont shoot at walls so I wouldnt know...however, I believe that if my bullet missed and went through my residence wall then it would probably have to go through another residence wall. If the bullet went through two walls, would it still be lethal?

I imagine that the speed of the bullet would be greatly slowed and the shape of the bullet would be distorted. I dont picture it having the same power.

gvf
January 5, 2008, 01:50 AM
The problem is when people - like your neighbors or wife - may be on the other side of the wall.

Playboypenguin
January 5, 2008, 01:59 AM
Does anyone have any verifiable examples of this ever happening during an HD situation?

CrazyIvan007
January 5, 2008, 02:20 AM
Something similar happened here in Denver.

Unknown targets hidden behind hidden walls can be a recipe for disaster.

http://www.rockymountainnews.com/news/2008/jan/03/man-court-new-years-slayings/

In this case, the shooter was being a fricking dumbazz, but it can happen with any discharge of a firearm.

If you are in a house or near any penetrable objects that could hide a person from your view, best to take a shot from the knee, shooting upward at your target if at all possible. There is a lot more wood and ability to stop a bullet in the roof structure than in the walls. Also, a bullet falling from the sky is pretty much harmless given enough distance to make a more downward trajectory than horizontal.

Playboypenguin
January 5, 2008, 02:23 AM
That is actually a brain dead idiot shooting into someone's house. Not a HD scenerio. Similar physics but I am wondering if it ever happens in a HD situation.

T. O'Heir
January 5, 2008, 04:15 AM
"...I dont picture it having the same power..." That doesn't matter. You are completely and totally, 100%, responsible for any shot you fire.
"...a bullet falling from the sky is pretty much harmless..." Nope. Think physics.

hogdogs
January 5, 2008, 10:01 AM
First off I think a bulet FALLING is not real likely to kill ya.
But My first concern is to the family and I can't do them a good service if I am slinging bullets toward them. From there on I am the owner of that projectile and responsible for it until it safely comes to rest. Manslaughter is "What If" my bullet....
Brent

JohnKSa
January 5, 2008, 01:28 PM
Guns fired exactly straight up.

Pistols & shotguns (with shot, not slugs) are unlikely to be lethal. Shot doesn't have the sectional density to have a really fast terminal velocity and pistol bullets (in the only known experiment where any were recovered after being fired straight up) tumble which dramatically increases the drag (and therefore dramatically decreases drag) on the "return trip".

Centerfire rifles have the potential to be deadly since the bullets (in the only known experiment where any were recovered) remain spin stabilized and fall base first at 300-400fps. That's not certain death, but with a little bad luck it can do the trick. A shotgun slug is big and heavy enough that I would expect it has the potential for real mayhem even at pretty low velocities--primarily as an impact weapon rather than a penetrating projectile.

Shooting at any significant angle from vertical (up but not exactly straight up) is very dangerous for two reasons.
The bullet typically remains stabilized and traveling nose forward which makes it much more aerodynamic. That means much higher terminal velocity.
The bullet comes down with a velocity that is the vector sum of both the terminal velocity and any remaining horizontal velocity not bled off by air friction.
These will definitely have enough "oomph" to be lethal and it's not that hard to find evidence to support that fact. I did an internet search looking for deaths from descending bullets some time ago and found enough documented instances to convince even the most skeptical. I don't know if that was posted here or on THR, but by now most of the links are probably dead anyway.

At any rate, I found deaths, injuries and even some descriptions of roof damage. There is also a fairly high-profile law in the U.S. against firing in the air that is named after a young girl killed by a descending bullet.

As to the original question: I have seen a case where a handgun bullet from a drive-by shooting (probably a .357Mag SWC) traveled through a typical woodframe house. In the front, out the back and through everything in between. It happened to take a path that didn't put a lot of intervening walls in the way, but a handgun bullet can definitely penetrate two exterior walls and some more besides. Bullets are good at going through things, that's what makes guns useful.

Offhand I don't know of any cases where a bullet left one house, entered another and accidentally killed someone in the second house but that would only speak to the likelihood of such an occurrence, not of the possibility which is fairly well established.

David Armstrong
January 5, 2008, 02:59 PM
There have been a few instances of people reported being hit through walls by police bullets after a gunfight, but I haven't heard on that in a long time, so I think the ammo selection may be very important there, as John points out.

As for falling bullets, we had an incident here around New Years. A .40 round, pretty much vertical (path seemed to be less than 5 degrees off vertical, but that is hard to tell w/multiple impacts) came down through a metal roof, 1/2" plywood, 6" insulation, a glass table top, and still penetrated a ceramic floor tile completely through into the floor decking.

Rob Pincus
January 5, 2008, 04:21 PM
We did a penetration test of various types of plausible home defense rounds for a DVD series last year and showed that just about any of them will go through at least 2 typical drywall walls (2 pieces each) with enough energy to hurt/kill. The 9mm Glaser and 12 gauge Birdshot were the exceptions.

-RJP

X-RAY
January 5, 2008, 04:56 PM
Check out theboxotruth.com . They (he) does a few drywall vs projectile penetration "tests".

sceva
January 5, 2008, 05:03 PM
My father-in-law and his brother once dedcided it would be a neat idea to shhot a .22 rimfire rifle at a target they drew on the garage wall. (adult beverages were involved) The bullet went thru the wood lap siding garage wall then thru both the inside and outside wall of the house and stopped when it hit the refridgerator.
I would never count on a residential wall slowing a bullet down enough to not be dangerous. Use common sense and be careful.

Tanzer
January 5, 2008, 05:16 PM
At the range, we had a ND in the cleaning room (.22 lr target pistol). It went through the wall, nicking a stud, off the furnace leaving a dent and took a chunk out of the cinder block wall. My kid was shooting his old pellet rifle at 2 layers of leftover drywall this summer and blowing chunks out of the back layer - not much Kinetic Energy in a .177 pellet compared to, say, a .40 S&W. I'd dare say inside walls weren't consructed to stop projectiles at high velocity.

Manedwolf
January 5, 2008, 10:36 PM
Some months ago, there was indeed a "through wall" death. It was some moron playing with their loaded AR in an apartment. The round went through the walls, through the headboard of a sleeping neighbor's bed, and into their head, killing them.

Just now, at new year's, I believe it was in Colorado, a rifle shot went into a house through the wall, killed a woman, and a girl beside her as well.

So yes, it can happen.

wogpotter
January 5, 2008, 10:52 PM
An uncle of mine killed his wife thru the floor of a 2 storey house.
I'd think a wall is less resistant to a bullet.

"You are completely and totally, 100%, responsible for any shot you fire."
True, so why take the risk?

Boris Bush
January 6, 2008, 09:31 PM
There is a very simple solution to not shoot through the walls and kill a neighbor. Get out of that comfy chair and go through you dwelling and figure out exactly where you might shoot, figure out where it will go (the projectile) if it does go through a wall. If the round has a potential to shoot through a wall and get a neighbor, I just wont shoot there.

I know every safe angle in my house and will shoot only if in them safe spots. Best one is right down the stairs. We all stay upstairs and I would only be shooting into my basement. I could use a 50 BMG if I wanted to........

Buzzcook
January 6, 2008, 10:23 PM
http://www.azstarnet.com/sn/hourlyupdate/218784.php

A 5-year-old boy was grazed by a bullet in the first hour of New Year’s Day, after someone fired what police called “celebratory” gunfire,” slammed through the roof and ceiling of his South Side home.

Celebratory gunfire is a major concern for the Tucson Police Department every year, as the stray bullets can cause serious injury and death to innocent people,

In a separate incident as the new year began, a bullet smashed through the kitchen ceiling of a house in the 1900 block of West Riverview Boulevard, near North Silverbell and West Grant roads, Pacheco said.
No one was injured by that bullet, he said.


Every New Years people shoot guns in the air and all most every year someone is injured or killed.
The bullet doesn't know that it's only supposed to intersect with bad guys.

kgpcr
January 6, 2008, 10:28 PM
There is no way a bullet fired straight up in the air is going to be any more lethal than a hailstone of the same size. Its the same as dropping it off of a sky scraper. It could kill but is very very unlikley to do so. now if you catch one in flight meaning an arc shaped trajectory thats another matter all together, those are deadly!

James K
January 6, 2008, 11:10 PM
It was no "scenario", but a man in a nearby town fired a shot from an SKS at his wife. Fortunately, he missed, but the bullet went out through his house wall, penetrated the exterior wall of a house 80 yards away, then went through an interior wall, out an exterior wall, and lodged in the exterior wall of a third house. Again very fortunately, no one was hurt. And that was a "low power" 7.62x39. Any questions?

As to bullets FALLING straight down, there is no practical difference in velocity and energy for bullets of the same weight no matter what kind of gun fired them. Terminal velocity is terminal velocity; the only difference would be due to air resistance. The hailstone does not provide an analogy, because it is much lighter than the bullet and its terminal velocity is lower due to air resistance. Mass does count. Which would you rather catch if it were falling from a building, a matzoth ball or a cannonball?

Jim

JohnKSa
January 7, 2008, 01:51 AM
There is no way a bullet fired straight up in the air is going to be any more lethal than a hailstone of the same size.Incorrect.

An object falling through air is subject to two forces, drag and gravity. Terminal velocity occurs when the two forces are balanced. A hailstone the same size as a bullet would have about the same drag, but the force of gravity is greater on the bullet since it is more dense (lead is denser than ice) and therefore weighs more (weight is the force on an object due to gravity). Therefore a bullet would fall faster than a hailstone of the same size.

Furthermore, a spin-stabilized bullet will fall either base or nose first rather than tumble. That reduces its drag considerably which means it will fall at a higher terminal velocity, perhaps double the velocity it would fall if tumbling. The tests I've seen suggest that falling pistol bullets will tend to tumble while falling rifle bullets tend to remain stabilized and fall back to earth base first.

Comparing bullets to hailstones is not an accurate way to assess the lethality of falling bullets.

It's kind of interesting that you make this comparison. Sometime ago I calculated the energy and velocity of various size hailstones. A local company was replacing their roof coating and wanted to know how to test it for hail resistance. One of the facilities personnel is a friend of mine and asked me to verify if the test that had been suggested to them was valid. (It involved dropping a steel ball bearing of specified weight from a specified height.) I did some research and calculations and determined that the test was valid based on the fact that the ball bearing imparted the same impact energy to the roof as a hailstone of the size that the roof material was rated for would. The embarassing part is that I enjoyed it. :D Oh well.

You are correct that a bullet that takes an arc-shaped trajectory (not fired exactly straight up) will come down at a much higher velocity than a falling bullet. In that case the velocity of the bullet is the vector sum of the terminal velocity and any retained horizontal velocity not lost to air resistance. Furthermore, in this case, the bullet will tend to remain spin-stabilized and traveling nose first which means the terminal velocity will be maximized due to the fact that drag is minimized. Definitely a recipe for disaster.

Adrian
January 7, 2008, 03:10 AM
Therefore a bullet would fall faster than a hailstone of the same size.

<nitpick>It would fall harder, not necessarily faster. Acceleration by gravity is about 9.8 m/s/s no matter how much or how little you weigh, up until you get near terminal velocity. F=MA; the greater force is due to the greater weight.</nitpick>

Sorry, my last girlfriend was a physics major and I picked up some of her habits. I suspect you knew all of this, given the rest of your post, but it's a stiff reflex.

Axion
January 7, 2008, 03:34 AM
It would fall harder, not necessarily faster. Acceleration by gravity is about 9.8 m/s/s no matter how much or how little you weigh, up until you get near terminal velocity.

More nitpicking (from a Mechanical engineer this time:D). Thing only fall at 9.81 m/s/s in the absence of drag. In all real life scenarios drag is present which means that the object with the higher sectional density (which most shooting enthusiasts know to be ratio of mass to cross sectional area) will not only accelerate faster, but reach a higher terminal velocity as well.

Note: Once you start talking about objects that tumble in flight the situation gets even more complicated as the relevant cross section is constantly changing.

JohnKSa
January 7, 2008, 09:30 AM
It would fall harder, not necessarily faster. Acceleration by gravity is about 9.8 m/s/s no matter how much or how little you weigh, up until you get near terminal velocity.Axion is correct, this is only true in the absence of drag (air resistance). This is a common misconception due to the fact that people remember basic physics problems but forget the assumptions and conditions specified in them. Your statement would be correct for falling objects in a vacuum but once you incorporate air resistance everything changes.

Here's a decent treatment of the topic from a source that most would consider unimpeachable.

http://www.grc.nasa.gov/WWW/K-12/airplane/falling.html

Manedwolf
January 7, 2008, 09:44 AM
Keep in mind that most guns "fired in the air" are not fired at 90 degrees to the ground, but at some angle, which means the bullet is traveling in a parabolic arc.

And depending on distance, coming down from that arc can indeed still be a bullet at lethal velocities, especially a pointed, more aerodynamic rifle bullet.

JohnKSa
January 7, 2008, 09:52 AM
Keep in mind that most guns "fired in the air" are not fired at 90 degrees to the ground, but at some angle, which means the bullet is traveling in a parabolic arc.Correct. A bullet traveling in an arc will have more velocity than a bullet that is simply falling--vector sums and all that...

Adrian
January 7, 2008, 12:07 PM
Axion is correct, this is only true in the absence of drag (air resistance). This is a common misconception due to the fact that people remember basic physics problems but forget the assumptions and conditions specified in them.

I don't think I forgot the assumptions, but isn't drag relatively negligible (relative to mass between a bullet and similarly-sized/reasonably spherical hailstone), up until you start getting near the hailstone's terminal velocity? I don't remember the details very well, but I think it's quite small next to the mass difference.

Once your hailstone hits terminal velocity, the bullet goes quite a bit faster, of course, but I'm not sure if the bullet gets there, starting from the ground and all.

It's too early to be doing physics problems. -.-

JohnKSa
January 7, 2008, 11:36 PM
...isn't drag relatively negligible...Air resistance is pretty significant. It's often neglected in problems given to students--not because it's negligible but because it can be quite difficult to calculate.

The more aerodynamic object will accelerate faster (since there's less force from air resistance fighting that acceleration) and will eventually reach a higher velocity before the air resistance balances the force of gravity.I'm not sure if the bullet gets there, starting from the ground and all.A bullet will travel upwards thousands of yards--experiments have shown a 30-06 rifle bullet will reach a height of around 9000 yards. That's enough time for the bullet to attain terminal velocity on the way down.

Interestingly enough, the person (Julian Hatcher) who did the experiment calculated that the bullet would have attained a height of over 21 MILES had there been no air resistance. Drag can not be neglected.

Adrian
January 8, 2008, 04:12 AM
Oh... right. That comment about "9000 yards" reminded me: bullets go really fast and the faster you go, the more drag matters.

I remember doing some simple drag problems and getting reasonably small answers (ideal non-tumbling cylinders and spheres, dropped from rest on a decent-height building), but... bullets go a lot faster than that. That's why they're useful.

Sorry for the hijack, everyone; I'm an idiot. http://s.gaiaonline.com/images/common/smilies/icon_gonk.gif

SMiller
January 21, 2008, 02:06 AM
Had a 9mm go off in my house, went through the carpet and foam padding, through the 2x10 hand cut floor and out of my basement wall that was concrete block, I wouldn't have wanted to be on the outside waiting for it!!! You would think it woundn't have made it through the floor. As for going through a wall, you know it's going to go through...

Covert Mission
January 21, 2008, 12:12 PM
These will definitely have enough "oomph" to be lethal and it's not that hard to find evidence to support that fact. I did an internet search looking for deaths from descending bullets some time ago and found enough documented instances to convince even the most skeptical.

Here's a first hand anecdotal example: I covered the first Gulf War as a photojournalist, with the 1st Marine Div, and ended up in Kuwait City the day it was liberated (SEALs and maybe CIA paras were there the day before, at least). The city was going totally wild with celebration for days, mainly along the seaside boulevard near the US Embassy. There were the usual wingnuts capping off their AKs into the air like firecrackers...hundreds of rounds. Here's the "joke": instead of aiming out over the sea just across the road, they were usually pointing their muzzles over the city. You guessed it...every day, people killed and wounded by falling projectiles. Pure genius!

On New Years, many LAPD patrol units working the late show pull into parking garages at midnight, because of falling lead.

SamHouston
January 21, 2008, 06:22 PM
A bit off subject but locally in a 3 story apartment complex where the 1st level offered attached garages. Several years back, Man decides to commit suicide by carbon monoxide poisioning in a closed garage. He was successful but also killed the guy asleep in the 2nd floor apartment above the garage.

Actions have consequences.

chopz
January 22, 2008, 10:24 PM
all physics aside, i seem to remember massad ayoob writing about shooting at a downward angle to avoid doing something stupid when you're not sure of your backstop. i'd rather risk my life dodging some bg with a limp than risk shooting the little girl down the street. no matter how brave a bg might be, i'd think a weapon pointed at his family jewels would be more than enough deterrent.

ShootemDown
January 23, 2008, 01:57 AM
I understand the bullet from the sky will fall at 9.8 meters per second max.

thats like being hit with a bullet coming at you appx 30 FPS

a reguarl bullet hitting you can be 1000 FPS.

how is a bullet falling straight from the sky kill you ? at 30 FPS ?

ShootemDown
January 23, 2008, 01:59 AM
all physics aside, i seem to remember massad ayoob writing about shooting at a downward angle to avoid doing something stupid when you're not sure of your backstop. i'd rather risk my life dodging some bg with a limp than risk shooting the little girl down the street. no matter how brave a bg might be, i'd think a weapon pointed at his family jewels would be more than enough deterrent.

I think if your bullet makes it through the BG, you wont have to worry about the wall behind him and the little girl behind that...

teeroux
January 23, 2008, 03:28 AM
I think if your bullet makes it through the BG, you wont have to worry about the wall behind him and the little girl behind that...

yeah well if you have two BGs without body armor lined up one behind the other ill bet my 357 mag i can bag both of them with one shot from the same.

i think you should always be worried about whats behind the target

ISC
January 23, 2008, 11:59 AM
OK, There is some good info here, but also some inaccuracies.

1) ACCELERATION due to gravity is 9.8 m/s². That's an approximate value, it decreases as an object's distance from the center of the earth increases. There is a difference between speed and accelleration, and they are related by the formula v=at (velocity = accelleration x time) . That means that it is travelling at 9.8m/s after one second, 19.6 m/s after 2 seconds, 29.4 m/s after 3 seconds, etc. Even if the accelleration is constant, the velocity would change.

2)In the case of the bullet fired into the air, the accelleration isn't constant. The net vector accelleration is the sum of the alleration due to gravity (which changes slightly as elevation increases) and negative accelleration (decelleration) due to wind resistance (which is a function of the projectile's speed, ballistic coefficient, flight profile, and air desity)

DaveBeal
January 23, 2008, 01:00 PM
they are related by the formula v=1/2at (velocity = 1/2 accelleration x time)

No, it's v = at. So, in the absence of drag, a dropped object is traveling approximately 9.8 m/sec after one second, 19.6 m/sec after two seconds, and so on.

You're thinking of d = (1/2)at^2, which describes distance traveled.

ISC
January 23, 2008, 01:35 PM
yep dave you're right. I corrected my post.

Hook686
January 23, 2008, 10:28 PM
I really hope it does not injure anyone. That said, I will only draw and shoot if I preceive a serious, or lethal threat immenanent against me. That trumps any 'maybe', 'possible', or 'might happen' scenarios. It is real, immediate and of a serious/lethal level to me.

allenomics
January 26, 2008, 09:26 PM
Obviously it does matter. Who's on the other side of the wall? What about the welfare of people who reside in townhomes, condominiums and work in next door office/business suites?

Doberguy
January 26, 2008, 11:05 PM
I have a keepsake of a shot going through one house and into another.
A jewelry box and a pocket watch

Neighbor cleaning his rifle (unsure of caliber need to ask parents) at night. Round goes out through exterior wall, travels approx. 60ft, goes through another exterior wall, travels about 10 ft passing over my crib (had I woke up like kids do in the middle of the night and stood up=headshot), enters a jewelry box, and stops hitting a pocket watch inside making a good dent breaking the watch.

Both homes stick framed with wood siding.

chopz
January 26, 2008, 11:19 PM
being a parent i don't have the luxury of worrying about imminent lethal threat to myself. god forbid i'll ever need to face someone down in my own home. but every scenario i've ever imagined always begins with me thinking where i would need to maneuver to to keep my son's room out of the line of my own fire, as well as any wild shots in my direction.

Aqeous
February 4, 2008, 07:04 PM
Originally posted:

"I believe that if my bullet missed and went through my residence wall then it would probably have to go through another residence wall. If the bullet went through two walls, would it still be lethal?"

The answer is absolutely and unquestionably YES . . .

"I imagine that the speed of the bullet would be greatly slowed and the shape of the bullet would be distorted. I don't picture it having the same power."

It would be plenty close . . . and here is why:

First off someone had already mentioned the box of truth website.
Heres the link:http://www.theboxotruth.com/docs/bot12.htm

It clearly demonstrates how a fairly light weight 9mm 155 gr JHP (THATS A HOLLOW POINT MIND YOU not a FMJ.) WILL cut through four fully insulated walls like a hot knife through butter. Check out the exit whole in the fourth wall set a full 40 feet away. There is no question that this would have be lethal would it have impacted someone. Everything he fires goes through all for wall with equally ease and potential lethality. The clear and final answer to your question is undeniably YES any bullet that permeates 2, 3, 4+ walls is invariably LETHAL.

I have taken a great deal of time collecting and interpreting ballistics and wound data over a considerable expanse of time. Just because most people cannot hit a target at 100 yards with a handgun does not mean that the bullet is not fully capable of traveling that distance with entirely lethal potential. Observe this link it demonstrates this point: http://www.youtube.com/watch?v=PKg9jISfOyg

As for a bullet shot into the air, the Mythbusters actually did this one. Unless a bullet is fired exactly, and I mean EXACTLY strait up against the force of gravity (not even a few degrees off) any bullet will fall back to earth on a what is called a ballistic trajectory and will impact the ground with LETHAL force. The wind trims a great deal of velocity off of the bullet in flight but I assure you, you cannot run out their and catch it as it falls. ---One specific instance of this I recall I think was actually aired quite some time ago on an old T.V show called Rescue 911. Some ignoramus's was shooting a revolver in their back yard at some soda cans. To make a long story short he missed one, the bullet passed over the backing and ended up falling into an old man sitting in a lounge chair hundreds of yards away. If you use the vast tool of information that is the Internet and really look you will find that their are actuality a considerable numerous reports where a rouge bullet apparently fired from nowhere fell from the sky and killed some unfortunate soul.

(Another report I recall off hand was of a couple who was speaking in there garage. The woman did not hear the sound of a gunshot, she only knew something was wrong when her husbands eyes rolled back in his head and he fell to the floor. (sorry for the graphic descriptions) When the cops arrived they had determined that a bullet fired from some unknown location had fallen through the roof and entered the mans head instantly killing him)

Ballistic trajectories are random and extremely dangerous. As are bullets that permeate walls (Buckshot from shotguns are not excluded as many people think. Buckshot will also permeate walls with potentially lethal energy.) It is imperative that people are aware of these facts and that this kind of information is spread until it becomes common knowledge . . .

Aqeous
February 4, 2008, 07:32 PM
"Had a 9mm go off in my house, went through the carpet and foam padding, through the 2x10 hand cut floor and out of my basement wall that was concrete block . . ."

1.) Did you by any chance see the actual exit of this round or did you assume that it permeated all the way through?

2.) Do you by any chance recall its brand and loading? I would like to know.

To be honest the carpet and floor I understand but it would be highly unusual for a 9mm to completely permeate a concrete block. Don't get me wrong, I'm not doubting you, it is only that most of the time you might expect a bullet of this type to either embed into the concrete or even more typically ricochet off of it after making a small crater. Could you explain this happening in greater detail for me I would very much like to know more about it?



The picture link below is what is more typical expected from of a 9mm impacting concrete.

warrior poet
February 4, 2008, 07:47 PM
Oy vay. Calculus... again... Okay. You asked for it. For something fired straight up, the bullet slows according to: Distance = initial (muzzle) velocity * time - 9.8 meters per second PER second * time. (This is the simplest one, not including wind resistance.) To include that.... You would also subtract the Area under the curve defined by the integral for the force of friction with respect to instantenous velocity. Leaving a system of equations with respect to three related variables- time, coefficient of friction and velocity.
YUCK! All of that will yield the max height of the bullet, which gives the gravitational potential energy. From that you again subtract the wind resistance, giving the kinetic energy on impact with the Earth.
All of this is moot, because it is IMPOSSIBLE to predict the bullet's coefficient of friction on the return trip b/c it is no longer stabilized by its spin. Net result... a statistical window in which three standard deviations will fall- roughly 99% of all bullets fired thusly. Would it kill when it hits... statistically no, but that only accounts for 99%.... there is always that slim chance that it might self-stabilize on the return trip, and be lethal. That is the mathematical answer... period. It isn't a physics problem, but one of statistics, b/c there is NO definitive way to predict wind resistance on the return trip. Okay?
Now, I'm going to enjoy some scotch... and kill off those offending brain cells I just used.

Aqeous
February 4, 2008, 08:15 PM
Mathematics is defiantly not my strength :) Let alone calculus, but I think you are expressing mathematically why a bullet will keyhole (impact sideways) after permeating and object or after bleeding off excessive speed am I right?

If I am right than you are right (I think :confused::)) and so their is far too many variables to calculate. Such as how many people per cubic mile inhabit a given area of space of which a falling rouge bullet may have a chance to impact. (am I right?)

And just because mathematically their are too many variables, that does not follow that bullets falling on ballistic trajectories have not proved themselves quite deadly time and time again.

JohnKSa
February 5, 2008, 03:01 AM
All of this is moot, because it is IMPOSSIBLE to predict the bullet's coefficient of friction on the return trip b/c it is no longer stabilized by its spin. ... Okay?Sounds good except that Hatcher's tests proved conclusively that a bullet can remain stabilized by spin on the return trip. In his 30-06 tests, the 150gr bullets remained stabilized and fell base first while the 175gr bullets tumbled on the return trip. The falling 150gr bullets were traveling around 300-400fps which is fast enough to penetrate the skull.

A tumbling bullet is going to have a much reduced terminal velocity, testing I've seen indicates that a typical, tumbling pistol bullet will fall at somewhere around 150fps, give or take. That's not likely to be terribly dangerous although I think it would make an impression on someone if it hit them. ;)

The more dangerous case than either tumbling or falling base first is a steeply elevated trajectory (when the bullet is fired steeply upward but not STRAIGHT upward). In that case the bullet will tend to remain stabilized and come down nose first with not only terminal velocity but also the remainder of the horizontal component of it's velocity left after drag. The resulting velocity is the vector sum of the terminal velocity plus the remaining horizontal velocity after drag loss. Definitely lethal potential.

nobody_special
February 5, 2008, 04:58 AM
Jumping in here since I'm a physicist... JohnKSa pretty much has it right.

Warrior Poet: You really can't ignore air resistance and expect to get a solution that is anywhere near correct. Air resistance is very significant in ballistics. Also, the bullet will remain spin-stabilized until something stops the spin; reaching the apex of a ballistic trajectory does not cause the spin to cease.

One thing about spin-stabilized objects is that you can get interesting behavior, such as precession (like the wobbling of a spinning top). Precession should increase drag somewhat, but some degree of axial stability remains; you won't get actual tumbling until the rotation of the bullet is mostly gone.

Aqeous
February 5, 2008, 10:30 AM
"bullet will tend to remain stabilized and come down nose first with not only terminal velocity but also the remainder of the horizontal component of it's velocity left after drag. The resulting velocity is the vector sum of the terminal velocity plus the remaining horizontal velocity after drag loss. Definitely lethal potential."

This is whats called a ballistic trajectory. And yes they are very dangerous, everyone should be aware of this fact.

tegemu
February 5, 2008, 12:44 PM
I once had a negligent discharge of a 1911. The .45 ACP bullet went through my wall and murdered my neighbors air conditioner. A $1360.00 negligence. The frightening part was that had it gone at a slightly different angle, it would have gone through his wlls with enough force to seriously wound someone in his house, if not kill them.

warrior poet
February 5, 2008, 12:51 PM
One, I never said to ignore wind resistance. Reread and you'll see that. Two, when speaking about mathematic prediction I assumed tumbling. No one ever specified a bullet type, so I went with what I believed to be a general answer. A hollow base bullet- like an SS109 M16 bullet (one I know REALLY well) would most certainly tumble when falling backwards, greatly reducing its rotational velocity (at least in the original vector). My point was that there are far too many variables to predict where the bullet will land and how it will be pointed when it hits. Bullet shape, crosswinds, temperature, altitude, and so on and on make an accurate prediction impossible- a three shot "group" MIGHT cover a three block radius. THAT'S why I said this isn't a calculus problem, but one for statistics. I'm sorry if I came across confusing. Believe it or not, I was trying to keep it relatively simple. As for whether it would be lethal on impact- I wouldn't want to be hit by it. ;)
Anyway, I think we've veered off the original thread (retained lethality after going through a wall) and I'm guilty of helping push it that way. As such... I'll apologize to the OP for helping hijack his post. SORRY.

nobody_special
February 5, 2008, 02:22 PM
A hollow base bullet- like an SS109 M16 bullet (one I know REALLY well) would most certainly tumble when falling backwards, greatly reducing its rotational velocity (at least in the original vector).

If it still has a high rotation (seems likely), it will not tumble upon falling backwards. Though incidentally, the larger caliber bullets will have a (significantly) higher moment of inertia, and thus are more likely to retain their rotation.

I wouldn't want to be hit by it. ;)

Me either. :D

Th0r
February 5, 2008, 05:01 PM
If I was defending my property this wouldnt be an issue. Firstly, I live in a fully detached 250 year old cottage. If I fired a bullet at a wall in my house, it would probably do damage to the stone work. If I fired a gun at the several wooden doors on my premises it might be a different issue.

Basically. I dont think if I were protecting my home and a bullet went through a door etc it wouldnt be a problem.

jabotinsky
February 8, 2008, 10:37 AM
My uncle Phil was sitting in his Brooklyn apartment years ago and the guy in the apartment below had a discharge cleaning his rifle that went through the floor, into the bottom of my uncle's foot, out the top, back into his shin, out the calf, into the back of the thigh, out the top and through a shoulder. He wasn't critically injured (!) suffered no long term effect and never bothered to sue the guy.


Which would you rather catch if it were falling from a building, a matzoth ball or a cannonball?

If it was my mother's matzoh ball, I'd rather take the cannonball...less dense...

mpage
February 11, 2008, 09:27 AM
Had a 9mm go off in my house, went through the carpet and foam padding, through the 2x10 hand cut floor and out of my basement wall

The only AD that I ever had was years ago when I fired an old Colt .32 auto into the floor; I had pointed it downwards, out of habit, when I squeezed the trigger and actually fired twice . Admittedly it was "only" a .32 but it did not penetrate the ceiling of the condo below me. Also, the rounds were Winchester Silvertips which may have had something to do with it. They broke up inside the padding and did not travel far.

On New Years, many LAPD patrol units working the late show pull into parking garages at midnight, because of falling lead.

In the last 15+ years it's been a little better since they made it a felony, but good God I was there in 1990 and it was like the Battle of Midway. Full auto, everything; the mad minute. I remember a round kicking up sparks a couple yards from me. Unbelievable.

Ridge_Runner_5
February 13, 2008, 02:09 AM
I had an AD in my home late last year with a 9mm carbine. It went through the floor of my room, through a heating duct, the ceiling of the room below and lodged in a wall stud in the room below mine. Fortunately I was the only one home at the time, but as a result, I personally do not keep loaded mags in the firearm. They may be with the firearm in the case, but in a seperate pocket.

My dad keeps his pistol with a loaded mag, empty chamber. Thats how i caused my AD, so I dont do it anymore.

M1911
March 26, 2008, 11:27 AM
Yes, a bullet that goes through a wall can kill someone on the other side. Here's a recent example:

Woman shot, killed by husband
Man used gun to make hole in wall

By RITA FLOREZ

A Deepwater woman died Saturday after being shot in the chest, according to the Henry County Sheriff’s Department.

Patsy D. Long, 34, was pronounced dead by Coroner Scott Largent just after 6 p.m.

Long was shot by her husband Ronald Long outside their home just after 6 p.m., while she was assisting him with the installation of a satellite television system, according to a written statement by the Sheriff’s Department.

Ronald Long, 39, of 956 SE 1121, Deepwater, told deputies he had made several attempts to punch a hole through the exterior wall of the house, according to the report. When that did not work, Long told deputies he used a .22-caliber handgun to shoot through the wall from inside the home. His second shot hit Patsy Long in the chest, the report stated.

Deputies are still investigating the death, and “Once we complete a diagram of the incident, we will be submitting everything to the prosecuting attorney and let him decide if he wants to press criminal charges,” said Major Robert Hills, of the Henry County Sheriff’s Department.

Hills said he could not speak for the prosecuting attorney, but normally in these types of cases the person would “get charged with a manslaughter of some sort.”

Henry County Coroner Scott Largent declined to release any information about Patsy Long’s death until the Sheriff’s Department finishes its investigation.

Original is here: http://www.sedaliademocrat.com/news/henry_7329___article.html/woman_county.html

Glenn E. Meyer
March 26, 2008, 11:54 AM
http://sports.espn.go.com/golf/news/story?id=3312784

Chef shot.

bigbadbowtie
April 4, 2008, 07:59 AM
Mythbusters did an episode on the bullet shot in the air scenario. You should be able to find it on youtube. Interesting info.

PT111
April 4, 2008, 08:43 AM
Two teen age girls were killed at Carowinds outside Charlotte several years ago by some fellows target shooting over a mile away. They ignored several safety rules and laws including the one about not having their automatic rifle licensed.

pax
April 4, 2008, 10:35 AM
Yeah, so what if it goes through a wall ...?

A post from one of my best buddies:

http://www.thefiringline.com/forums/showpost.php?p=810175&postcount=82

Marnie, my high-school sweetheart, and my best friend's sister, was killed by an AD. She was at home lying in bed reading a book. Her nine month old son was lying in the bed next to her. Her husband was in the living room watching TV.

Across the street in a different apartment complex, a young man was excitedly playing with his brand new AR14. With some foolish lack of thought, he chambered a round and for some reason even he couldn't explain, pulled the trigger. The bullet went through his wall, across the street, through the wall of her bedroom and into Marnie's brain. It killed her instantly. The baby wasn't hurt. Not directly anyway.

For a moment of stupidity, the young man spent time in jail and will never be allowed to own a gun again for the rest of his life. Marnie's husband and child both lost even more.


pax

pfch1977
April 5, 2008, 06:41 PM
Now I didnt mean just any bullet. Of course, a rifle is not meant for home use.

This brings back one of my original posts where I asserted the CX4 storm would be the ideal home defense weapon.

Usually when I fire off a .40 caliber pistol, I feel as if I am on the deck of the USS New Jersey when a big 16 incher is going off. Lots of flash and bang.

However, the .40 coming from a long barrel is much more satsifying.

Check out this youtube video.

http://www.youtube.com/watch?v=4e2d-MznC9M


Look at how smooth of a operation this is when cooking off some rounds. Not much kick and jiggle from the long gun. Not much flash and bang as if your firing a civil war musket.

DRD
April 5, 2008, 06:55 PM
A number of years ago, a neighbor's 12 year old son got ahold of his .22 rifle on Saturday morning when daddy wasn't home.
The kid fired a .22LR at a bird, in flight. The bullet punched through the siding on the house next to me, and continued through the insulation and inside drywall. It then crossed through the kitchen, went through an inside wall (total of 2 layers of drywall) and finally embedded in the drywall at the far side of the living room.
Fortunately, no one was home.