You guys might google around for some of the "suicide by sub 12 ft/lb air rifle" articles I read recently. Seems about 3 or so people each year in the UK end their lives with non FAC air rifles (i.e sub 12 ft/lb). Interesting that something that 'low powered' can do the job. I dont want anything as hard as a bullet hitting me at 300 fps. Paintballs were bad enough....
MythBusters: Bullets Fired Straight Up
- Thread starter MikeJackmin
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slopemeno said:
Yes, but...
Presumably all of them were point-blank contact shots to the head through the thin part of the temple, or possibly into the heart via the sternum. A bit different than dropping at 300fps onto the top of the cranium. Also, do these suicides take into account air embolisim, or secondary tissue disruption from the blast of air following the pellet?
I DO believe that a +/- 300fps terminal velocity bullet dropped with <60ft/lbs of K.E. CAN kill. But I'm firmly in the camp that it can't do it reliably. I agree that most, but not all, of the "falling" bullet deaths are at angles significantly less than 90° where horizontal velocity is adding significant fps and ft/lbs and giving the bullet a point-first orientation.
TexasRifleman
Moderator Emeritus
Camp David said:
"Thou shalt not add thy velocity to the velocity of an object leaving thy hand."
If you are rotating around the earths axis at 26,000 mph, so is the bullet.
If what you state was true, then if I stood in the front of a 747 going 500mph, and I jumped up, I should smack the back wall of the fuselage.
Ain't gonna happen.
Shalako
Member
Not only is the relative velocity of the bullet travelling normal to your point on the earth's surface, the atmosphere is also moving in rotation around the earth's axis. The velocity of the atmosphere though is not constant across its thickness and its decrease is nonlinear due to the variation in densities and viscosities of the different strata.
If this was a test question, I'd pick c.)
If this was a test question, I'd pick c.)
IndianaDean
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What we need is for a whole big group of Al Quaida and Taliban guys to stand out in the open, fire their guns in the air and let the bullets come back down to test the theory.
Let me see. First, a "bullet fired into the air" is not the same as a "bullet fired straight up". A shot fired with the barrel at an upward angle, which is almost any aimed shot fired at a target at any significant distance, is "fired into the air." At other than a 90 degree angle, it will retain at least some of its initial (muzzle) velocity when it comes down.
A shot fired straight up will stop in the air, losing all its initial velocity, and start to fall, just as if it were dropped from that height. Its velocity cannot exceed terminal velocity, which is about 300fps. This could be dangerous, but for an ordinary rifle bullet, not normally lethal.
The Coriolis effect has nothing to do with the earth turning under a bullet, and that does not happen. A bullet fired straight up and having nothing acting on it but gravity, will come down at the point where it was fired. (Of course, this just doesn't happen in the real world; a true 90 degrees is not easily attainable, and there are too many factors influencing any bullet fired through the air any time.)
Jim
A shot fired straight up will stop in the air, losing all its initial velocity, and start to fall, just as if it were dropped from that height. Its velocity cannot exceed terminal velocity, which is about 300fps. This could be dangerous, but for an ordinary rifle bullet, not normally lethal.
The Coriolis effect has nothing to do with the earth turning under a bullet, and that does not happen. A bullet fired straight up and having nothing acting on it but gravity, will come down at the point where it was fired. (Of course, this just doesn't happen in the real world; a true 90 degrees is not easily attainable, and there are too many factors influencing any bullet fired through the air any time.)
Jim
TexasSIGman said:
Jim Keenan said:
Actualy...
It does.
Although in the realm of arrows and centerfire ammunition the effect is negligable to the point of immeasurability. And it does not apply to a straight up shot... So it does not come into play in this debate. (Phew)However, when the Germans were using the massive Krups rail-carriage "Paris Gun" in WWI, and the lesser known "V3" (Hitler's Vengance 3) booster cannon to try and shell England from across the channel, the Earth's rotation had to be taken into account when plotting the firing solutions to obtain accurate fire.
http://en.wikipedia.org/wiki/Coriolis_effect
The Coriolis Effect is also what makes Hurricaines spin. The Earth's rotational velocity is less at higher latitudes where the circle being traced over 24 hrs. is shorter in length than one traced by a point on the equator. If we can all agree that Velocity=Distance/Time and the Earth spins once in 24 hours, than the longer circle that the Equator traces has to be moving faster than any other latitude. Essentialy, the southeren half of the hurricaine is being swung around faster than the northeren half, and that makes it want to spin.
And it is indeed true. Because of the faster movment at the Equator, you actualy way about a pound less than you would at the poles! The centrifugal force (Actually, technicaly "conservation of angular momentum") at the Equator actualy cancels out gravity just a tad more than it does anywhere else.
So when plotting long range ballistic solutions the Earth's spin does have to be taken into account, or you won't hit what your aiming at. So it's moot for this discussion, but it is a real factor in ballistics.
Crosshair
Member
*Note to self: Wear Hard Hat.*
bogie
Member
Camp David said:
Er... Sometimes those gusts of wind can blow a bullet _into_ the group.
cz75bdneos22
Member
will it kill you....
Obviously you don't know, but are willing to believe the mythbusters...YMMV i hope you never find out for yourself...i like to learn from the mistakes of other's first, before making my own...he,he!
Obviously you don't know, but are willing to believe the mythbusters...YMMV i hope you never find out for yourself...i like to learn from the mistakes of other's first, before making my own...he,he!
The terminal velocity of a bullet is not going to be very great. In my younger and dumber years, i spent a good bit of time in freefall. I'd be willing to bet money that an ordinary 9mm, 45acp, or 308 bullet would fall slower than a skydiver (120 mph). Don't ask me how I know this, lets just say that I jumped over farmland and sometimes other things fell out of the plane with me.
If the bullet continues its gyroscopic spin during its entire flight, the bullet would stay pointed upwards and land base first, presenting a smaller aspect ratio to the wind, making it fall faster. If it stopped its gyroscopic spinning during freefall, it would start to tumble and this would slow it down some pretty significant amount.
You mean we don't have any active skydivers here who would be willing to let go of a bullet in freefal to see if it would stay falling with them? (Believe it or not, this could be done very safely.)
If the bullet continues its gyroscopic spin during its entire flight, the bullet would stay pointed upwards and land base first, presenting a smaller aspect ratio to the wind, making it fall faster. If it stopped its gyroscopic spinning during freefall, it would start to tumble and this would slow it down some pretty significant amount.
You mean we don't have any active skydivers here who would be willing to let go of a bullet in freefal to see if it would stay falling with them? (Believe it or not, this could be done very safely.)
AZ Jeff
Member
As the original poster mentioned in his opening post, Maj. Julian Hatcher did experiments on bullets fired vertically. His tests, performed in Miami and Daytona, Fla., in 1919-1920, were done firing .30/06 service bullets out of a Browning machine gun that had very carefully aligned on a tripod so as to have a true bore axis of 90 degrees to the horizon.
Hatcher's experiments showed the 150 grain flat based ball bullet of the day came down BASE FIRST, and would dent a pine board to the depth of about 1/16 inch. Calculations showed this bullet was returning to earth at about 300 fps. (Bullets return to earth base first because the center of gravity for most bullets is further to the base of the bullet than is the center of drag.)
For the 718 grain .50 BMG bullet of the day, terminal velocity was measured at about 500 fps.
Based on this, we can conclude that lighter and/or slower bullets than the two examples above might likely be very less-than-lethal if fired truely straight up.
(All of this can be found in the book "Hatcher's Notebook" starting on about page 505, for those of you interested in reading more.)
The reason that bullets fired on New Year's Eve (and the common Middle Eastern "bullets of joy") can cause more damage and death than that shown above is because RARELY are bullets TRULY fired directly vertically, and almost always have a significant horizontal velocity component, even when fired basically skyward. This horizontal component results in the equivalent of what machine gunners call "plunging fire", and is quite lethal.
The affects of the Coriolis acceleration, winds aloft, and other similar factors have little effect on bullets fired skyward when one considers that, in almost all cases, the shooter firing bullets "straight up" is really doing so without any real attempt to place the bore truly perpendicular to the ground. That lack of precision overshadows all other small scale considerations.
Hatcher's experiments showed the 150 grain flat based ball bullet of the day came down BASE FIRST, and would dent a pine board to the depth of about 1/16 inch. Calculations showed this bullet was returning to earth at about 300 fps. (Bullets return to earth base first because the center of gravity for most bullets is further to the base of the bullet than is the center of drag.)
For the 718 grain .50 BMG bullet of the day, terminal velocity was measured at about 500 fps.
Based on this, we can conclude that lighter and/or slower bullets than the two examples above might likely be very less-than-lethal if fired truely straight up.
(All of this can be found in the book "Hatcher's Notebook" starting on about page 505, for those of you interested in reading more.)
The reason that bullets fired on New Year's Eve (and the common Middle Eastern "bullets of joy") can cause more damage and death than that shown above is because RARELY are bullets TRULY fired directly vertically, and almost always have a significant horizontal velocity component, even when fired basically skyward. This horizontal component results in the equivalent of what machine gunners call "plunging fire", and is quite lethal.
The affects of the Coriolis acceleration, winds aloft, and other similar factors have little effect on bullets fired skyward when one considers that, in almost all cases, the shooter firing bullets "straight up" is really doing so without any real attempt to place the bore truly perpendicular to the ground. That lack of precision overshadows all other small scale considerations.
bogie
Member
I remember seeing some WWII era small finned lead projectiles (about the size of a .45ACP round) in a Lancaster county museum about 30 years ago (sigh...). The story was that they were designed to mess up either troops or roofs when dropped en masse from bombers... I don't think I'd want to be standing in the open.
Taurus 66
Member
A falling bullet could kill, it may not kill. There are a lot of variables. Here are just a few:
- The bullet weight and mass, angle of descent ...
- Did the bullet strike on it's nose?
- Does the bullet achieve terminal velocity before impact?
- Were there any crosswinds, up drafts, or sudden down drafts?
- Was the victim standing still at time of impact, walking, running ...?
- Is the victim male or female, a child or adult?
- Is the injury blunt trauma or invasive?
- Was the impact invasive to the point of affecting organs and/or major blood vessels?
VARifleman
Member
BS on everything has the same terminal velocityMrTuffPaws said:
.Drop a penny and a coffee strainer next to eachother. they have different terminal velocities.
Just to make sure you understand this and don't mess other bits of gravity up...
Terminal Velocities are different for different objects depending on their size, weight, and shape.
Gravitational force is different for different objects. Gravitational Force is weight and we all know that our weights are different.
The acceleration due to gravity is the same for all objects. That's because F=ma, and when Fgrav=Fair resistance, that means that the net force on a free falling object is zero, thus acceleration is 0. This is why the terminal velocities differ on different shapes and weights, the shape decreases or increases the ballistic coefficient, and the weight is the gravitational force.
MrTuffPaws
Member
trapperjohn said:
Thanks, I was trying to show that weight had little to do with TV.
MrTuffPaws
Member
VARifleman said:BS on everything has the same terminal velocity
Drop a penny and a coffee strainer next to eachother. they have different terminal velocities.
Just to make sure you understand this and don't mess other bits of gravity up...
Terminal Velocities are different for different objects depending on their size, weight, and shape.
Gravitational force is different for different objects. Gravitational Force is weight and we all know that our weights are different.
The acceleration due to gravity is the same for all objects. That's because F=ma, and when Fgrav=Fair resistance, that means that the net force on a free falling object is zero, thus acceleration is 0. This is why the terminal velocities differ on different shapes and weights, the shape decreases or increases the ballistic coefficient, and the weight is the gravitational force.
Again, if you read my post, I say if you ignore air resistance, and TV has nothing to do with weigth or mass, but shape and size.
VARifleman
Member
UGH!!!!trapperjohn said:
10/5=2...
volume goes up by two, that means that the radius has changed by a factor of 2^(1/3) which means that surface area has changed by a factor of 2^(2/9) which is less than two. This is why it has a higher terminal velocity. :banghead: :banghead:
You all are going to give me a stroke if you keep talking this nonsense.
VARifleman
Member
As pointed out THERE IS NO TERMINAL VELOCITY WITHOUT AIR RESISTANCE!! Air resistance is the only thing limiting speed as you fall. Otherwise, you'd acelerate until you hit somthing. Since some of what affects air resistance is shape and size, you are complete contradicting yourself.MrTuffPaws said:
VARifleman
Member
Air resistance, the only thing that affects TV, increases by a factor of velocity^3, with larger weights and fairly good profiles, it does not change it dramatically, but with smaller weights and bad profiles, it changes it considerably.MrTuffPaws said:
SkyDaver
Member
MrTuffPaws said:
MrTuffPaws, I was an active skydiver for over 16 years, and have nearly 500 freefalls.
Weight has a GREAT deal to do with terminal velocity. You are correct that objects fall at the same rate in a vacumn, but in the air, or other medium, weight is a major factor.
Over my skydiving experience, my weight varied from about 165 to 200 lbs.
At 165, in a polycotton suit, I struggled to fall as fast as most other jumpers. At 185 in that same suit, I had no problems. At 200lbs, I was setting the fall rate (other jumpers were trying to keep up with me) My shape and cross sectional area were close to constant.
At 200 lbs, in a smooth nylon suit, I fell like a greased anvil.
You can prove that weight matters yourself. Go buy some table tennis balls. Make a small hole in one, and fill it with liquid (Elmer's glue might be good, since it would set after a bit.)
Drop both of them from outstretched arms. The filled one will hit the ground first.
As you note in the rest of the post, if the bullet continues to spin (and it will, based on Hatcher's tests) it will fall much faster since a tumbling object is far less aerodynamic.
Falling bullets can certainly be lethal, a bit of internet search will turn up fatalities, I did some research a couple of years back around New Years and came up with a large number of respectable news sources reporting fatalities from falling bullets.
The speculation about HOW lethal they are is pretty crazy, IMO. After all, you have an 80% chance of surviving an AIMED shot from a handgun in a violent encounter. I'd say that it's less likely you'd die from getting hit by a falling bullet, but it can and DOES happen.
Hatcher's numbers (energy threshold for fatal wounds) are misleading. It is possible to be killed by a projectile having far less energy than he states. The one or two airgun fatalities each year prove it.
Bottom line. Falling bullets can be fatal--no speculation or mythbusting necessary, you can easily find well documented instances.
Crosshair said:
Just what I was thinking. From what I've read, a bullet of decent size can indeed kill when falling at terminal velocity if it gets a lucky hit.
However, the amount of additional protection needed is construction hard hat level, not kevlar military helmet level.
armyranger
Member
A bullet or any object reachs "terminal velocity" when it reachs its max speed, with is 33 feet per sec. Nothing will fall faster than 33 ft per sec unless some other force was used i.e. throwing it down, ect. So no, it will not kill you, ( ever been to south america or mexico, they shoot hand guns in the air to celebrate all sorts of events)
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