Anonymous-0
Well-known Member
If a rifle is fired straight up in the air how high will the bullet go before it stops and begins to fall back to earth. For this question let say we are using a 30/06 with a muzzle velocity of about 2800fps.
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Anonymous-0
Well-known Member
Need more information, what is the bullet weight and ballestic coefficient. Are you planning on doing this at sea level or on top of a tall mountian ?
Please dont try this as it is dangerous because of the large potential energy of the projectile when striking the ground after a fall from such a great height. Repeat, this could hurt or kill a person on the ground.
My calculations show about 37161.22 meters 37.161 km, or right around 23 miles in height, and would take about 174.17 seconds to get there. At this instant in time, the projectile would be completely depleated of its kinetic energy, have zero velocity.
If you are trying to make a spacecraft, you would be short by at least 50 miles, since earths gravitational space starts around 120 km (75 mi). Plus the winds at the higher elevations are moving at quite high rates of speed
if you are thinking maybe someone shot down the satelite with a firearm, i would say it was highly unlikely.
My calculations show about 37161.22 meters 37.161 km, or right around 23 miles in height, and would take about 174.17 seconds to get there. At this instant in time, the projectile would be completely depleated of its kinetic energy, have zero velocity.
If you are trying to make a spacecraft, you would be short by at least 50 miles, since earths gravitational space starts around 120 km (75 mi). Plus the winds at the higher elevations are moving at quite high rates of speed
if you are thinking maybe someone shot down the satelite with a firearm, i would say it was highly unlikely.
the tractor vet
Well-known Member
I see you did not watch the MITH BUSTERS as they did that and at this moment the results have escaped me .
Anonymous-0
Well-known Member
Check out Myth Busters,and on results they had trouble finding the rounds.
MarkB_MI
Well-known Member
- Location
- Motown USA
Hmm,
I also get 23 miles [i:654c4848f0]in a vacuum[/i:654c4848f0].
The kinetic energy is 1/2mv<sup>2</sup>, where m equals mass of the projectile and v is the muzzle velocity.
At the apogee of its arc all kinetic energy is converted into potential energy. Potential energy is mgh, where m is mass, g is the acceleration of gravity (32 ft per second squared) and h is the elevation.
So:
mgh = 1/2mv<sup>2</sup>
h = (1/2v<sup>2</sup>)/g
h = (1/2 x 2800<sup>2</sup> ) / 32
h = 122,500 ft
h = 23.2 miles
Of course, the real height will be MUCH less. Projectiles traveling at over two times the speed of sound lose velocity very quickly. 1000 yard highpower competitors have to use fairly heavy bullets to keep them from going subsonic before they get to the target. I don't know how to do the calculations, but I would be very surprised if a typical rifle projectile would go over a mile vertically. Someone with access to a ballistics program can do the calculations, based on the ballistic coefficient of the particular bullet.
I also get 23 miles [i:654c4848f0]in a vacuum[/i:654c4848f0].
The kinetic energy is 1/2mv<sup>2</sup>, where m equals mass of the projectile and v is the muzzle velocity.
At the apogee of its arc all kinetic energy is converted into potential energy. Potential energy is mgh, where m is mass, g is the acceleration of gravity (32 ft per second squared) and h is the elevation.
So:
mgh = 1/2mv<sup>2</sup>
h = (1/2v<sup>2</sup>)/g
h = (1/2 x 2800<sup>2</sup> ) / 32
h = 122,500 ft
h = 23.2 miles
Of course, the real height will be MUCH less. Projectiles traveling at over two times the speed of sound lose velocity very quickly. 1000 yard highpower competitors have to use fairly heavy bullets to keep them from going subsonic before they get to the target. I don't know how to do the calculations, but I would be very surprised if a typical rifle projectile would go over a mile vertically. Someone with access to a ballistics program can do the calculations, based on the ballistic coefficient of the particular bullet.
Anonymous-0
Well-known Member
The "edge of space" is the altitude accepted as being above the earth's atmosphere, not it's gravity. The moon orbits the earth due to the pull of earth's gravity so the earth's gravitational field extends far past that. A 30/06 fired strait up probably doesn't reach even the stratosphere.
There have been super cannons designed that would fire a shell high enough to be above much of the atmosphere and travel very long distances.
There have been super cannons designed that would fire a shell high enough to be above much of the atmosphere and travel very long distances.
Your question reminds me of some testing the Army did at Yuma Proving ground where they were doing exactly that, only with a 175mm Long Tom! They had developed a new fuse for the 175mm shell and wanted to fire some using inert rounds and recover the fuses as undamaged as possible. The solution was to fire them vertically. That way, the round would go right straight up and come to a stop without arcing over and fall back to earth base first thus sparing the fuse from impact damage. They used cables to stabilize the tube and they fired those things for days. Cinetheodolite cameras positioned on adjacent mountaintops took pictures of the rounds from the time they left the tube until they struck the earth. I don't know how high they went. All I did was fly the helicopter out to where they landed where the survey crews could get a fix on us while the observer threw a flag in the hole. Those rounds sunk in so deep that they used a specially built bulldozer (FMC) to dig them out.
Anonymous-0
Well-known Member
The test they performed on the Myth Busters show, provided 2 scenarios, one being if the rifle was straight vertically, true 180 deg or perpendicular to the ground, the projectile would reach it's max height and tumble back to earth, relatively close to where it was fired. If you tilt the rifle, (even slightly) so that the bullet trajectory is an arc, the projectile continues in its path until gravity pulls it down. The bullet is apparently more dangerous if it maintains an arc or somewhat horizontal trajectory, vs perpendicular trajectory, and they cited an instance where a person was killed by a bullet in this manner.
They fired an M1 Garand, and some 9mm pistol rounds on the salt flats somehwere, they did retrieve the 9mm bullets, I forget if they were able to find any rifle bullets. I also forget whether they tested the lethality of a bullet striking a person when fired perpendicular to the earth, though I sure would not want to test that theory, stray or not, bullets fired in an unsafe direction, at something that does not absorb impact, especially rifle ammunition, is very dangerous.
They fired an M1 Garand, and some 9mm pistol rounds on the salt flats somehwere, they did retrieve the 9mm bullets, I forget if they were able to find any rifle bullets. I also forget whether they tested the lethality of a bullet striking a person when fired perpendicular to the earth, though I sure would not want to test that theory, stray or not, bullets fired in an unsafe direction, at something that does not absorb impact, especially rifle ammunition, is very dangerous.
t=(v-v0)/a
t= (0-2800fps)/(-32.2 ft/s^2) = 86.95 sec. or 174 sec round trip. (assumes no air friction)
It would reach an altitude of 121739 feet. (again assuming no air friction.)
The reality is that this assumption is bad, as the shock loss and drag on the bullet is large and cannot be ignored.
t= (0-2800fps)/(-32.2 ft/s^2) = 86.95 sec. or 174 sec round trip. (assumes no air friction)
It would reach an altitude of 121739 feet. (again assuming no air friction.)
The reality is that this assumption is bad, as the shock loss and drag on the bullet is large and cannot be ignored.
Not much of it there any more...saw a map, looks like all if not most of Cibloa is a wild life refuge, as is a good portion of the Kofa Firing Range...my Grandfather trained there w/ Patton prior to heading over for the big one...Upstate, NY here so I am missing that weather as I do every year at that time!
Here in AZ we have "Shannon's Law", where it's illegal to discharge a weapon into the air with-in any city limits in the State.
Shannon Smith, a 14yo, was standing in her backyard talking on the phone when a stray bullet hit her in the top of her head killing her instantly.
I believe it was the next year, that another child bent over too pick up something on the ground and was hit with a 50cal BMG projectile in the neck. They showed x-rays of that one on the local TV. Wow what a huge looking bullet that was. The kid recovered.
Phoenix went as far as to install microphones across the city and say the police can track a firearm discharge to the exact house it was fired from. Every July 4th they brag how they caught several people using the microphones. No follow up's tho.
T_Bone
Shannon Smith, a 14yo, was standing in her backyard talking on the phone when a stray bullet hit her in the top of her head killing her instantly.
I believe it was the next year, that another child bent over too pick up something on the ground and was hit with a 50cal BMG projectile in the neck. They showed x-rays of that one on the local TV. Wow what a huge looking bullet that was. The kid recovered.
Phoenix went as far as to install microphones across the city and say the police can track a firearm discharge to the exact house it was fired from. Every July 4th they brag how they caught several people using the microphones. No follow up's tho.
T_Bone
Speaking of Patton. I took Carl Mydans (famous Life magazine photographer) out to Patton's old marshalling area and then we followed the tank tracks which were still visible north up toward Las Vegas. He got a lot of photos of that and it was really interesting to me. The railroad came right by Patton's main camp and the Army had an agreement with the railroad that when passenger trains came by the train would stop if there were soldiers waiting on the platform. Well, the trains weren't stopping. Patton heard about it and when he heard the next passenger train coming he went out and stood right in the middle of the tracks with one of his guns drawn. The engineer just barely got the train stopped and Patton was in the cab with a cocked revover to the engineer's head yelling at him for not stopping for soldiers. From then on, the trains stopped whether there were soldiers there or not.
buickanddeere
Well-known Member
Depending on the ballistic coefficient of the projectile. Most "small" bullets fall back to earth at just below the speed of sound.
When the bullets tries to exceed the speed of sound the shock waves tend to make the bullet tubbles and increase drag. Which slows the bullet.
Still a 180G .308 caliber at 1100ftps would do damage.
When the bullets tries to exceed the speed of sound the shock waves tend to make the bullet tubbles and increase drag. Which slows the bullet.
Still a 180G .308 caliber at 1100ftps would do damage.
They musta spent alot of time, $, and effort getting Cibola (North of main post all cleaned up. about 80% of it was used as a Lase test sight and was supposed to be secure. People alwys wandering in and finding old stuff after a storm...one cpl found an old WWII grenade and actually drove it 40 or so miles South to our MP station! Used to have to ride in helicopter patrols to keep folks out during Deer season.
I've nothing but anecedotal information about Patton and I know he was a 'hero'.........my Dad came home with 5 battle stars from the ETO, Normandy, the Low Countries, the Rhine, Germany, Ardennes Breakthrough (called by the media the Battle of the Bulge) (been a long time since I looked at his service records and I may have some of them wrong). He was in a Field Observation Bn, which was directly subordinate to the XIX Corps and was in amongst Patton's Army for months and months, 'though not part of it. He said that Patton was universally despised by his men, the rank and file.
ScottyHOMeY
Well-known Member
Every object with mass has what is called a terminal velocity. It's the fastest it will travel under the influence of gravity through the air that surrounds it. Propellants can, of course, make it go faster, but when friction overcomes the effect of the propellant, it will settle down to the it terminal velocity.
So anybody that's ever set up a scope or iron sights and played with different loads, knows about setting up their elevation for distance to target. The usual diagram shows an arc, with the gun aimed higher than the target, the slug rising on the arc from the barrel and then falling under the effect of gravity to hit the target.
Question is this. Does a bullet fly straight on a downhill shot as long as the downward velocity of the slug is more than its terminal velocity or does gravity add to the downward velocity immediately?
Picture sittin' on a rock overlookin' a beech grove waitin' for Old Mossyhorns to walk into view. A 500-foot downhill shot over the ground. Your barrel is at 45 degrees below level. The round has a muzzle velocity of 3000 ft/sec, so the bullet leaves the barrel falling/going downhill at about 2000 ft/sec. The slug itself has a terminal velocity of 600 ft/sec. Instead of following the arc of a shot on flat ground, will the bullet fly straight until it slows down to the point that its downward speed is less than the terminal velocity of 600 fps, and to what degree, if at all, does the effect of gravity help the slug maintain its speed or alititude for as long as it exceeds the terminal velocity?
So anybody that's ever set up a scope or iron sights and played with different loads, knows about setting up their elevation for distance to target. The usual diagram shows an arc, with the gun aimed higher than the target, the slug rising on the arc from the barrel and then falling under the effect of gravity to hit the target.
Question is this. Does a bullet fly straight on a downhill shot as long as the downward velocity of the slug is more than its terminal velocity or does gravity add to the downward velocity immediately?
Picture sittin' on a rock overlookin' a beech grove waitin' for Old Mossyhorns to walk into view. A 500-foot downhill shot over the ground. Your barrel is at 45 degrees below level. The round has a muzzle velocity of 3000 ft/sec, so the bullet leaves the barrel falling/going downhill at about 2000 ft/sec. The slug itself has a terminal velocity of 600 ft/sec. Instead of following the arc of a shot on flat ground, will the bullet fly straight until it slows down to the point that its downward speed is less than the terminal velocity of 600 fps, and to what degree, if at all, does the effect of gravity help the slug maintain its speed or alititude for as long as it exceeds the terminal velocity?
A friend of mine was a Chief Warrant Officer in a maintenance unit that at several times was attached to the Third Army. He hated Patton because Patton required officers to wear neckties. He was considered an officer even though most of the time he was getting his hands dirty.
Sagebrusher
Member
Bill,
For this and other in-depth answers to your question I recommend you buy or borrow a copy of "HATCHER"S NOTEBOOK" by Julian S Hatcher, Maj Gen U.S.A.(ret.)(now deceased)) ISBNO-8117-0614-1
See Chapter XX "Bullets from the Sky"
Gen Hatcher calculated through mathematical means verified by live fire that the 150 gr .30 cal M2 bullet fired at a 90 dgree angle with a mv of 2,700 fps would acheive a maximum height of around 9,000 feet. The bullets took approximately 18 seconds to reach max altitude and an average 31 seconds to return for roughly 50 seconds to return after firing. The return times and velocity were dependant on whether the bullets returned base down (the fastest return) or tumbled end over end (the slowest.)
Gen Hatcher felt that during the last few thousand feet of fall that the bullet's return was at a constant 300 fps with an attnedant 30 foot pounds of energy.
Bullets with higher ballistic coefficients travel higher/farther and thus take longer to return.
Most of the casualties you hear and read about are produced by ignorant buffoons haphazardly firing weapons at less than perpendicular angles resulting in arcing trajectory curves where the bullet remains point on with, usually, more velocity than a bullet returning to earth in freefall mode.
For this and other in-depth answers to your question I recommend you buy or borrow a copy of "HATCHER"S NOTEBOOK" by Julian S Hatcher, Maj Gen U.S.A.(ret.)(now deceased)) ISBNO-8117-0614-1
See Chapter XX "Bullets from the Sky"
Gen Hatcher calculated through mathematical means verified by live fire that the 150 gr .30 cal M2 bullet fired at a 90 dgree angle with a mv of 2,700 fps would acheive a maximum height of around 9,000 feet. The bullets took approximately 18 seconds to reach max altitude and an average 31 seconds to return for roughly 50 seconds to return after firing. The return times and velocity were dependant on whether the bullets returned base down (the fastest return) or tumbled end over end (the slowest.)
Gen Hatcher felt that during the last few thousand feet of fall that the bullet's return was at a constant 300 fps with an attnedant 30 foot pounds of energy.
Bullets with higher ballistic coefficients travel higher/farther and thus take longer to return.
Most of the casualties you hear and read about are produced by ignorant buffoons haphazardly firing weapons at less than perpendicular angles resulting in arcing trajectory curves where the bullet remains point on with, usually, more velocity than a bullet returning to earth in freefall mode.
Glen D Anderson
Member
Very interesting info. thurlow, thanks for sharing!
MarkB_MI
Well-known Member
- Location
- Motown USA
Any knowledgeable rifleman will tell you that when you shoot on an incline, whether downhill OR UPHILL, your bullet will hit higher than it would if you were shooting the same distance horizontally.
But you're trying to make it too complicated. The effect of gravity on the bullets velocity is insignificant relative to aerodynamic drag. The effect of gravity is to cause the bullet to "fall" from its original, straight-line trajectory. How far the bullet drops is a function of both the actual force of gravity and how long it takes for the bullet to get from the muzzle to the target. The faster the bullet, the less time gravity has to act on the bullet and the less the bullet drops from the straight-line trajectory.
When you are shooting horizontally, the force of gravity is normal (perpendicular) to the bullet's trajectory. So the full force of gravity (32 ft/s<sup>2</sup>) is working to deflect the bullet from its path. But on a incline, the force of gravity is split into two components; one that deflects the bullet and another that either accelerates or decelerates the bullet. As stated earlier, the acceleration/deceleration effect can be ignored. So what we're concerned with is the force that is normal to the bullet's path. And that force is the acceleration of gravity (32 ft/s<sup>2</sup>) times the cosine of the angle of trajectory. So for a 45 degree slope, the force of gravity is .707 (the cosine of 45) times 32 ft/s<sup>2</sup>.
Fortunately, you don't need to take your slide rule into the field with you. Just remember that when shooting uphill or downhill, hold the same sight position you would use for the [i:654c4848f0]horizontal[/i:654c4848f0] distance to the target. So in the case of your 500 ft shot down a 45 degree incline, hold as if the target were only 350 feet away. Simple.
But you're trying to make it too complicated. The effect of gravity on the bullets velocity is insignificant relative to aerodynamic drag. The effect of gravity is to cause the bullet to "fall" from its original, straight-line trajectory. How far the bullet drops is a function of both the actual force of gravity and how long it takes for the bullet to get from the muzzle to the target. The faster the bullet, the less time gravity has to act on the bullet and the less the bullet drops from the straight-line trajectory.
When you are shooting horizontally, the force of gravity is normal (perpendicular) to the bullet's trajectory. So the full force of gravity (32 ft/s<sup>2</sup>) is working to deflect the bullet from its path. But on a incline, the force of gravity is split into two components; one that deflects the bullet and another that either accelerates or decelerates the bullet. As stated earlier, the acceleration/deceleration effect can be ignored. So what we're concerned with is the force that is normal to the bullet's path. And that force is the acceleration of gravity (32 ft/s<sup>2</sup>) times the cosine of the angle of trajectory. So for a 45 degree slope, the force of gravity is .707 (the cosine of 45) times 32 ft/s<sup>2</sup>.
Fortunately, you don't need to take your slide rule into the field with you. Just remember that when shooting uphill or downhill, hold the same sight position you would use for the [i:654c4848f0]horizontal[/i:654c4848f0] distance to the target. So in the case of your 500 ft shot down a 45 degree incline, hold as if the target were only 350 feet away. Simple.
I think there is no real definition of the exact location of earths outer atmosphere, it all depends on what you are trying to do, escape earths gravity, or skip along the outer atmosphere, or just get zero g's. 62 miles is kicked around a lot, as well as 175 miles, either way, even with ideal conditions, a bullet will not travel 23 miles straight up. 23 miles is the book equation, that conveniently ignores stuff like friction. Strange as it sounds, that is how people are taught.
buickddeere
Member
I did say about 1100fps.
Anonymous-0
Well-known Member
They also did a test that proved that you cant get shocked peeing on a electric fence wire .Plenty of farm boys known better.I was out one night marking some insulators that were arcing over.I was kneeling down marking a bottom insulator.I spit and got a good shock in the mouth.I could send the Mythbusters and old weed chopper charger that would change the out come of their test.
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