Cardiac Injury Caused by a Celebratory Bullet

[Brian Pfleuger]

Well, I got closer to 200 fps, but I may have gotten some units mixed up.

I'm sure it varies a bit with different rounds. Mythbusters tested 9mm and 30-06 if I remember correctly (might have been 45acp but I don't think so). They never did find any of the rifle rounds that were actually fired and I suspect that if there is a weakness in their numbers it would be there. The rifle round would go far higher and would have far more rotational speed. Not that the height would really matter but the rotation certainly would. If the rifle round remained stable and fell butt first it would certainly be going much faster.

I do recall a study some years ago, done at a university, I could swear it was Yale but I can never find the information, where they drew conclusions that were essentially a combination of the studies cited above. They said that a rifle bullet would remain spin stabilized and fall butt first and that said rifle bullets had enough speed to put a substantial dent in plywood and 2X4s hit on the way down, concluding essentially that it would hurt like hell but would not be fatal.

 

[Housezealot]

my buddy was telling me when he was in the sandbox there was several occasions were they investigated gunfire and it turned out to just be celebratory gunfire from weddings nothing gets a party going like the 82nd airborne busting in armed!

 

[SteelJM1]

Remember that the people who subscribe to the theory that falling bullets only reach terminal velocity are ignoring one fact: That theory only works of the bullet is fired exactly straight up. The more you vary from perpendicular, the more forward velocity the bullet retains.

The farther from straight up a bullet is fired, the faster it will be going when it hits the ground. The vertical and horizontal velocities are independant of each other. On the vertical component, the bullet will slow down to a stop, and start back towards the earth. On the horizontal, it will slow down due to drag. Given enough distance (which I don't think any bullet will have the required distance) it will reach its terminal velocity (and be going straight down for all practical purposes), but before then it will be travelling faster.

A bullet fired straight down would strike the ground at full muzzle velocity (plus any gravitational acceleration, minus drag) and a bullet fired at an angle of 60-80 degrees above the horizontal would still retain quite a bit of energy when it struck the ground

Nope. A bullet fired straight down into the ground (if from high enough up) will slow down due to drag, just as it slows down from air drag when fired from horizontal. Given enough time it would eventually slow down to it's terminal velocity which would be quite high given that it's going pointy end first, cutting through the air. Again I think that the distance it would need to slow down to TV would be miles and miles, but the air drag at, say, 2800 fps is far stronger than the gravitational acceleration.

 

[SteelJM1]

I do recall a study some years ago, done at a university, I could swear it was Yale but I can never find the information, where they drew conclusions that were essentially a combination of the studies cited above. They said that a rifle bullet would remain spin stabilized and fall butt first and that said rifle bullets had enough speed to put a substantial dent in plywood and 2X4s hit on the way down, concluding essentially that it would hurt like hell but would not be fatal.

I think that if i were to hit you on top fo your head with a hammer with a .30 cal head with enough force that it would leave substantial dents in 2x4, it would hurt a bit more than hell.

Sorry, but people have already died from falling bullets. To say otherwise is nonsense.

 

[Brian Pfleuger]

Sorry, but people have already died from falling bullets.

No, they have not. They have died from bullets that maintained a ballistic-type trajectory and, as such, were still traveling at bullet-like speeds. I have never seen nor heard of an incident wherein someone was killed by a falling bullet.

 

[SteelJM1]

Now we're just getting into semantics. It's nigh impossible to shoot a bullet perfectly straight up and have it come down in the same spot, so it will keep its ballistics in some way shape or form. Anyway you cut it though, physics is physics. The vertical and horizontal components are separate from each other. A bullet fired straight up and hitting 3000' feet will hit the ground in the vertical component at the same speed that a bullet fired at 45 degrees and hits 3000'. The horizontal component adds resultant speed, but it's effect will vary depending on how high the bullet goes.

 

[JustDreadful]

And the heavier the bullet, the higher the terminal velocity.

The name Galileo ring a bell? Drag determines terminal velocity, not weight.

 

[SteelJM1]

Weight is a factor in TV. Look it up.

 

[Brian Pfleuger]

A bullet fired straight up and hitting 3000' feet will hit the ground in the vertical component at the same speed that a bullet fired at 45 degrees and hits 3000'. The horizontal component adds resultant speed, but it's effect will vary depending on how high the bullet goes.

That is inaccurate.

A bullet fired at a 45 degree angle will not come to a stop before hitting the ground. A bullet fired straight up will come to a complete stop vertically and nearly complete stop horizontally and will only have the energy of being dropped from whatever height at which it stopped. The bullet fired at the 45 degree angle will have whatever is left of it's original energy from being fired, which will only be degraded by wind resistance and whatever the horizontal (relative to the path of the bullet, 50% in the 45 degree example) component of gravity happens to be, IN ADDITION to whatever energy it gains from dropping from it's ultimate height.

If you want to really complicate things, once the 45 degree bullet begins the downward portion of flight, gravity is actually aiding it's velocity, in that it will be partially counteracting wind drag, again, at whatever horizontal component it happens to be.

 

[divemedic]

Nope. A bullet fired straight down into the ground (if from high enough up) will slow down due to drag, just as it slows down from air drag when fired from horizontal.

Isn't that what I said when I said:

A bullet fired straight down would strike the ground at full muzzle velocity (plus any gravitational acceleration, minus drag)

and this:

A bullet fired straight up and hitting 3000' feet will hit the ground in the vertical component at the same speed that a bullet fired at 45 degrees and hits 3000'.

Since velocity is a vector quantity, that is speed plus direction, the VELOCITY of the bullet is the sum of all forces acting upon it: Gravitational acceleration, drag, lift, the initial velocity, and a host of other factors.

The bullet which is fired into the air can retain enough velocity to penetrate tissue. I have seen it. Anything else is trying to use mathematics to prove to me that bumblebees cannot fly.

 

[Brian Pfleuger]

The bullet which is fired into the air can retain enough velocity to penetrate tissue. I have seen it.

I think pretty well every bullet ever fired has been "into the air".

The question is in regards to a bullet fired absolutely, positively, completely STRAIGHT UP.

Nobody is trying to say that bullets fired "into the air" in any general sense, are not lethal.

 

[hogdogs]

http://www.clickorlando.com/news/5784022/detail.html

ORLANDO, Fla. -- A 26-year-old woman watching New Year's Eve fireworks in Orlando was seriously injured when she was struck in the face by a stray bullet fired into the air during the celebration, according to a Local 6 News report.

Investigators said Ruby Cintron was standing on the north shoreline of Crooked Lake in the Highlands Lake subdivision off Hiawassee Road after midnight Sunday when she was hit near the eye by the .45-caliber bullet.

Last New Year's Eve, a stray bullet fired more than 2,200 yards away struck and killed a 75-year-old man.

Police hope the person who fired the shot will turn themselves into authorities.

tons more if you search [killed by falling bullet] on google...
Brent

 

[SteelJM1]

That is inaccurate.

A bullet fired at a 45 degree angle will not come to a stop before hitting the ground.

In the vertical component, yes it will. And it will be slowing horizontally the entire time.

A bullet fired straight up will come to a complete stop vertically and nearly complete stop horizontally and will only have the energy of being dropped from whatever height at which it stopped. The bullet fired at the 45 degree angle will have whatever is left of it's original energy from being fired, which will only be degraded by wind resistance and whatever the horizontal (relative to the path of the bullet, 50% in the 45 degree example) component of gravity happens to be, IN ADDITION to whatever energy it gains from dropping from it's ultimate height.

The horizontal component of its energy will decrease during the entirety of the flight, because the horizontal speed of its flight is decreasing due to air drag, with nothing to counteract it. Given enough time, it will stop moving horizontally completely and come straight down, but I doubt that there's a deep enough pit in the earth for this to be a practical scenario. A bullet fired at 45 degrees will not hit the earth at 45 degrees.

If you want to really complicate things, once the 45 degree bullet begins the downward portion of flight, gravity is actually aiding it's velocity, in that it will be partially counteracting wind drag, again, at whatever horizontal component it happens to be.

Gravity is aiding its velocity ONLY downwards and to its TV again, while it is still slowing down due to drag horizontally. Give it a long enough time to fly and its horizontal velocity will be negligible and only add a small amount of resultant speed to the bullet, while it will be falling at TV or close to it down. Doing the calculations, for a 180gn .30 caliber bullet that noses over in flight, its TV would be ~390 fps. And it would only take a little more than 13 seconds to get there. If fired straight up, and falls ass first, it will come down at faster than 190fps (i calculated that one using a flat plate but that simplifies the fact that the cone section of the bullet will be acting as a drag reducer and lower its Cd).

 

[SteelJM1]

Divemedic: yeah but when you say that a bullet fired from the air will hit the ground at full MV, it gives the sense that it will hit the ground at faster than MV which is simply not the case. Sure gravity is accelerating the bullet towards the earth, but the drag from the air especially at MV speeds (acceleration the other way) far outweighs the gravitational acceleration and slows the bullet down.

It's the same as a bullet fired at a target slows down due to drag. Gravity will just make the rate of deceleration (or acceleration in reverse) 9.8 m/s^2 less than if fired horizontally at a target.

 

[PT111]

If someone tells me that they are going to drop a bunch of .30 cal bullets from a helicopter at 3,000 feet and want me to see where they fall, I am going to be sure that I have something substantial covering my body. I don't trust Mythbusters or any of you enough to stand out there and thinking they won't hurt if they hit my head.

 

[SteelJM1]

PT: Trust me, i'm telling you they will HURT! Or kill you!

But it would need more like 7000' to get to its TV (just crunched the numbers )

 

[Brian Pfleuger]

A bullet fired straight up...

The horizontal component of its energy will...

There will be no horizontal component of a bullet fired STRAIGHT UP.

Doing the calculations, for a 180gn .30 caliber bullet that noses over in flight, its TV would be ~390 fps. And it would only take a little more than 13 seconds to get there. If fired straight up, and falls ass first, it will come down at faster than 190fps (i calculated that one using a flat plate but that simplifies the fact that the cone section of the bullet will be acting as a drag reducer and lower its Cd).

Which goes to the whole point..... which was that a bullet fired STRAIGHT UP will not have enough muzzle energy to kill, while one fired at an angle very likely will...

If someone tells me that they are going to drop a bunch of .30 cal bullets from a helicopter at 3,000 feet and want me to see where they fall, I am going to be sure that I have something substantial covering my body. I don't trust Mythbusters or any of you enough to stand out there and thinking they won't hurt if they hit my head.

One: 3000 feet is irrelevant, they will reach terminal velocity in about 400 feet. You could drop them from 20,000 feet and they wouldn't hurt any more than from 400 feet.

Two: We are attempting to make a distinction between "hurt" and "kill". Hurt is a big YES as confirmed by the Mythbusters. Kill is a big NOT LIKELY, with the ASSUMPTION of being fired STRAIGHT UP.

 

[hogdogs]

Us splitting hairs over this discussion is actually silly as heck until the celebratory shooters are firing exactly straight up everytime!
Brent

 

[SteelJM1]

Which goes to the whole point..... which was that a bullet fired STRAIGHT UP will not have enough muzzle energy to kill, while one fired at an angle very likely will...

No, because the angle won't matter much. After 30 seconds of flying though the air, the horizontal component will add negligible speed to the bullet because it will have been bled off. It would have been as if it was fired almost straight up into the air.

Listen, if a bullet is coming donw at 300 fps, straight down, it hits you at 300fps. If it comes down at 300 fps and it's slowed from its initial horizontal speed to 100 fps (sideways), it will hit you at 316 fps. A little more ouch, but not that much.

 

[Brian Pfleuger]

Us splitting hairs over this discussion is actually silly as heck until the celebratory shooters are firing exactly straight up everytime!
Brent

Well, yeah, it becomes a physics discussion. The prudent argument, which I would gather we all agree on, is DON'T.