Discussion:
Falling bullets
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Ralph Mowery
2016-02-21 16:53:05 UTC
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I have seen many discussions and data on shooting a bullet streight up in
the air and how it will do very little damage when it falls back down. What
I would like to see is at what angle can you be off vertical and do little
damage when it comes down.

It would be good to see several examples such as a 22 LR, 357 mag, 44 mag
out of a hand gun and a 223 and 30/06 out of a rifle. Say how far off
vertical could the gun be before it would wound or penetrate some thin
material such as 1/8 inch wood.

It is easy to find the balistic data on shallow elevations and norman
shooting, but could one shoot at 80 deg instead of 90 deg and when the
bullet lands not have much enegery , or will it have a lot ?

[MODERATOR: Your Humble Moderator suggests tracking down a copy
of "Hatcher's Notebook" since there are partial answers to your
question there. If he recalls correctly, then the answer is a
bit nuanced.]
TimR
2016-02-21 22:31:42 UTC
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On Sunday, February 21, 2016 at 11:53:09 AM UTC-5, Ralph Mowery wrote:
# I have seen many discussions and data on shooting a bullet streight up in
# the air and how it will do very little damage when it falls back down. What
# I would like to see is at what angle can you be off vertical and do little
# damage when it comes down.
#
# It would be good to see several examples such as a 22 LR, 357 mag, 44 mag
# out of a hand gun and a 223 and 30/06 out of a rifle. Say how far off
# vertical could the gun be before it would wound or penetrate some thin
# material such as 1/8 inch wood.
#
# It is easy to find the balistic data on shallow elevations and norman
# shooting, but could one shoot at 80 deg instead of 90 deg and when the
# bullet lands not have much enegery , or will it have a lot ?
#
# [MODERATOR: Your Humble Moderator suggests tracking down a copy
# of "Hatcher's Notebook" since there are partial answers to your
# question there. If he recalls correctly, then the answer is a
# bit nuanced.]

Hatcher had unlimited resources and a lot of time on his hands. I'm in awe of the
experiments he did up at Aberdeen Proving Ground.
Ralph Mowery
2016-02-21 23:39:57 UTC
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"TimR" <***@aol.com> wrote in message news:naddse$ruh$***@news.albasani.net...
# On Sunday, February 21, 2016 at 11:53:09 AM UTC-5, Ralph Mowery wrote:
# # I have seen many discussions and data on shooting a bullet streight up
# in
# # the air and how it will do very little damage when it falls back down.
# What
# # I would like to see is at what angle can you be off vertical and do
# little
# # damage when it comes down.
# #
#> # [MODERATOR: Your Humble Moderator suggests tracking down a copy
# # of "Hatcher's Notebook" since there are partial answers to your
# # question there. If he recalls correctly, then the answer is a
# # bit nuanced.]
#
# Hatcher had unlimited resources and a lot of time on his hands. I'm in
# awe of the
# experiments he did up at Aberdeen Proving Ground.
#

I have a copy of Hatchers Notebook in pdf form and I looked through it and
did not see anything that would answer my question. They have some data for
normal firing at angles up to about 20 deg and data for vertical, but I did
not see anything that would indicate any small arms that are fired at say
from around 45 to 85 deg off the horizontal.
Martin Eastburn
2016-02-22 10:28:05 UTC
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When you shoot up gravity and air pressure retard the bullet. The
bullet comes to zero speed and does a nose over. (if it does) and begins
to fall. Gravity is pulling it faster and faster.

If you believe in math, the velocity would be close to the same as shot
up. Parabola.

Cannons do this all the time, just not straight up. 45 degrees gives
max distance. Above that and the shot starts dropping closer to the
cannon.
This naturally assumes nominal wind.

People are killed every year in LA from gun fire shot up into the air
during Christmas and other dates.

The bullet doesn't loose mass. Velocity is the only difference an it is
almost the same smacking into your foot.

Martin
TimR
2016-02-22 18:08:18 UTC
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On Monday, February 22, 2016 at 5:28:09 AM UTC-5, Martin Eastburn wrote:
# When you shoot up gravity and air pressure retard the bullet. The
# bullet comes to zero speed and does a nose over. (if it does) and begins
# to fall. Gravity is pulling it faster and faster.
#
# If you believe in math, the velocity would be close to the same as shot
# up. Parabola.


Don't do the math yourself. It's all been worked out. Just type the parameters into
any ballistics program.

Chairgun is a good one and it's free.

http://www.hawkeoptics.com/chairgun.html
Ralph Mowery
2016-02-22 21:17:36 UTC
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"TimR" <***@aol.com> wrote in message news:nafiqi$5rr$***@news.albasani.net...
# # If you believe in math, the velocity would be close to the same as shot
# # up. Parabola.
#
#
# Don't do the math yourself. It's all been worked out. Just type the
# parameters into
# any ballistics program.
#
# Chairgun is a good one and it's free.
#
# http://www.hawkeoptics.com/chairgun.html
#
#

Just tried it, Like many programs it is limiated to more or less normal
shooting. The range seems to max out at 1000 yards. Not enough range for
bullets fired way up in the air.
AUGOLDMINER
2016-10-09 23:49:13 UTC
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On Monday, February 22, 2016 at 10:08:21 AM UTC-8, TimR wrote:
# On Monday, February 22, 2016 at 5:28:09 AM UTC-5, Martin Eastburn wrote:
# # When you shoot up gravity and air pressure retard the bullet. The
# # bullet comes to zero speed and does a nose over. (if it does) and begins
# # to fall. Gravity is pulling it faster and faster.
# # If you believe in math, the velocity would be close to the same as shot
# # up. Parabola.
# Don't do the math yourself. It's all been worked out. Just type the parameters into
# any ballistics program.
# Chairgun is a good one and it's free.
# http://www.hawkeoptics.com/chairgun.html

i use to go to mud dry lake in NV and i always wondered about the .50 bmg bullets
i found nose up in the dry lake bed mud.
this dry lake was used to training gunners on bombers during WW2

i got to talking to a couple old guys that did weapons testing at NOTS China
Lake Calif and found that if you shoot a gun near straight up the bullet
will go up till it runs out of speed then because of gyroscopic action it will
fall base down till it hits the ground.

Anything less the about 60degrees the bullet will fly nose high till about
30 degrees.

another thing many do not know is a FMJ bullet fired into thick ice will keep
spinning for 10 to 30 sec.



Ralph Mowery
2016-02-22 18:08:19 UTC
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"Martin Eastburn" <***@consolidated.net> wrote in message news:naenrl$fko$***@news.albasani.net...
# When you shoot up gravity and air pressure retard the bullet. The
# bullet comes to zero speed and does a nose over. (if it does) and begins
# to fall. Gravity is pulling it faster and faster.
#
# If you believe in math, the velocity would be close to the same as shot
# up. Parabola.
#
# Cannons do this all the time, just not straight up. 45 degrees gives
# max distance. Above that and the shot starts dropping closer to the
# cannon.
# This naturally assumes nominal wind.
#
# People are killed every year in LA from gun fire shot up into the air
# during Christmas and other dates.
#
# The bullet doesn't loose mass. Velocity is the only difference an it is
# almost the same smacking into your foot.
#

From reading Hatchers that only happens in a vacuum. On earth the air
resistance plays a very big part in the returning speed of a bullet.
I think he said a 30/06 would land at abot 300 fps if returning from
straight up.
The returning bullets only put a dent in some wood it hit. Saw a Myth
Buster show where they shot some hand guns straight up and they did not
penetrate very much in the ground where they hit.

Somewhere between 0 and 90 deg from horizontal there should be an angle
where the returning velocity will be below what Hatcher called a disabling
wound. They would be a hit on the body and not something like a hit in the
eye and then to the brain.
TimR
2016-02-22 21:17:34 UTC
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On Monday, February 22, 2016 at 1:08:21 PM UTC-5, Ralph Mowery wrote:
# From reading Hatchers that only happens in a vacuum. On earth the air
# resistance plays a very big part in the returning speed of a bullet.
# I think he said a 30/06 would land at abot 300 fps if returning from
# straight up.

Hatcher went out in a boat on calm days and shot rifles straight up. He never could spot the splashes until he went to full auto.

He also tried turning down the barrels of rifles on a lathe, a little bit at a time, to see how thin he could get them before they blew up.

Cool guy, lots of ideas. Well worth reading.
Joe Pfeiffer
2016-02-22 21:17:33 UTC
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Martin Eastburn <***@consolidated.net> writes:

# When you shoot up gravity and air pressure retard the bullet. The
# bullet comes to zero speed and does a nose over. (if it does) and begins
# to fall. Gravity is pulling it faster and faster.
#
# If you believe in math, the velocity would be close to the same as shot
# up. Parabola.

That same drag will work to reduce velocity both going up and coming
down (unlike gravity, which is always pulling down). The result is that
it won't be coming down nearly as fast as it went up.

# Cannons do this all the time, just not straight up. 45 degrees gives
# max distance. Above that and the shot starts dropping closer to the
# cannon.
# This naturally assumes nominal wind.

It actually assumes zero drag.

# People are killed every year in LA from gun fire shot up into the air
# during Christmas and other dates.

We all hear about "this can happen", but I don't know when I've ever
actually read about a case that involved a near-vertical bullet coming
down and hurting someone.
Ralph Mowery
2016-02-23 00:04:53 UTC
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"Joe Pfeiffer" <***@cs.nmsu.edu> wrote in message news:nafttc$seh$***@news.albasani.net...
# # People are killed every year in LA from gun fire shot up into the air
# # during Christmas and other dates.
#
# We all hear about "this can happen", but I don't know when I've ever
# actually read about a case that involved a near-vertical bullet coming
# down and hurting someone.
#

If the bullets are almost vertical it is doubtful if anyone was killed.
However if just shot up in the air , say at 45 deg, then it would be
possiable.
I often wonder if any of the mideastern people are killed with all that
shooting of the automaitcs in the air. Seems that almost every day there
is a news clip showing someone shooting in the air just to make noise.
Gunner Asch
2016-02-27 11:46:20 UTC
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On Mon, 22 Feb 2016 21:17:33 +0000 (UTC), Joe Pfeiffer
<***@cs.nmsu.edu> wrote:

#
## People are killed every year in LA from gun fire shot up into the air
## during Christmas and other dates.
#
#We all hear about "this can happen", but I don't know when I've ever
#actually read about a case that involved a near-vertical bullet coming
#down and hurting someone.

Indeed. Most of the injuries and fatalities Ive investigated and read
about were from rounds fired at various angles..not 12 Oclock
S***@hotmail.com
2016-06-02 19:42:01 UTC
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# Joe Pfeiffer <***@cs.nmsu.edu> wrote:

#Martin Eastburn <***@consolidated.net> writes:
#
## When you shoot up gravity and air pressure retard the bullet. The
## bullet comes to zero speed and does a nose over. (if it does) and begins
## to fall. Gravity is pulling it faster and faster.
##
## If you believe in math, the velocity would be close to the same as shot
## up. Parabola.
#
#That same drag will work to reduce velocity both going up and coming
#down (unlike gravity, which is always pulling down). The result is that
#it won't be coming down nearly as fast as it went up.
#
## Cannons do this all the time, just not straight up. 45 degrees gives
## max distance. Above that and the shot starts dropping closer to the
## cannon.
## This naturally assumes nominal wind.
#
#It actually assumes zero drag.
#
## People are killed every year in LA from gun fire shot up into the air
## during Christmas and other dates.
#
#We all hear about "this can happen", but I don't know when I've ever
#actually read about a case that involved a near-vertical bullet coming
#down and hurting someone.

I have been hit on the top of the head by number five shot coming back
down. It hurt. From the impact, which had the feeling of 'egg shell',
I could tell that anything heavier would go through my skull.

TE Lawrence in 'The Seven Pillars of Wisdom' told that in camp they
had casualties (dead) from what he called 'joy firing' into the air
and the rounds coming back down.
Mike Fontenot
2016-02-23 00:04:55 UTC
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On 2/22/16 3:28 AM, Martin Eastburn wrote:

# When you shoot up gravity and air pressure retard the bullet. The
# bullet comes to zero speed and does a nose over. (if it does) and begins
# to fall. Gravity is pulling it faster and faster.
#
# If you believe in math, the velocity would be close to the same as shot
# up. Parabola.
#

Gravity exerts a constant vertically downward force on the bullet,
proportional to the bullet's mass. The air exerts a retarding force
(directed opposite to the velocity), proportional to the square of the
velocity of the bullet, and it is independent of the bullet's mass. When
the bullet starts coming back down, the velocity increases until the
increasing drag force becomes equal and opposite to the constant
gravitational force, so that the net force is zero. Thereafter, the
velocity stays the same ... it's called the "terminal velocity". A very
light bullet (like a .22 long-rifle bullet) has such a small mass that
the terminal velocity is very slow ... harmless unless it hits you in
the eye. A 240 gr .44mag bullet is heavy enough to be harmful. I
suspect a .50 would likely penetrate your scull and be lethal.
Martin Eastburn
2016-06-03 12:18:22 UTC
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"They" kill people in LA every year. The population is into
shooting up in the air to celebrate. LA tries to hold off that but
it comes anyway.

Martin
Peter Franks
2016-06-15 01:18:06 UTC
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On 2/22/2016 2:28 AM, Martin Eastburn wrote:
# When you shoot up gravity and air pressure retard the bullet. The
# bullet comes to zero speed and does a nose over.

Won't nose over due to gyroscopic effect due to rotation. A bullet may
be spinning at 120,000 RPM out of the barrel, and will be still spinning
by the time it hits whatever it hits.

# (if it does) and begins
# to fall. Gravity is pulling it faster and faster.

Until it reaches terminal velocity. Shot on the moon, the bullet
(assuming it didn't have sufficient escape velocity) would be travelling
the same speed as when shot; on the earth, it is far slower, a few
hundred FPS if I recall.
TimR
2016-06-15 20:13:13 UTC
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On Tuesday, June 14, 2016 at 9:18:08 PM UTC-4, Peter Franks wrote:
# On 2/22/2016 2:28 AM, Martin Eastburn wrote:
# # When you shoot up gravity and air pressure retard the bullet. The
# # bullet comes to zero speed and does a nose over.
#
# Won't nose over due to gyroscopic effect due to rotation. A bullet may
# be spinning at 120,000 RPM out of the barrel, and will be still spinning
# by the time it hits whatever it hits.
#
.

I'm pretty sure a falling bullet without spin will stabilize base first. It's a mass stabilized projectile at that point. The center of mass is near the base.

It is likely impossible to shoot a bullet absolutely straight, so I think as long as spin remains, a bullet will travel nose first in an arc, both on the way up and the way down.

However I have seen oblong holes in targets, so it is evident that some bullets do not have sufficient spin to travel nose first, and slower bullets would be more affected by this.
Martin Eastburn
2016-06-15 11:12:16 UTC
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I think if an arc is shot - who can shoot 90 degrees upwards - do we
have to account for speed of the earth.... This can be a very complex
simple complex problem. And the arc continues onward through the arc.
So spin continues.

Simply if the bullet arcs it does as you say. 99.99999999% are like that!

If the odd perfect shot where in theory it stalls and noses over,
I suspect the spin starts in the fall.

We get into metal types and teh land cuts on the bullet so much to
figure with. How about north / south of the equator...

Enough to make a person nuts just thinking.

Martin
Gunner Asch
2016-06-15 20:13:14 UTC
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On Wed, 15 Jun 2016 11:12:16 +0000 (UTC), Martin Eastburn
<***@consolidated.net> wrote:

#I think if an arc is shot - who can shoot 90 degrees upwards - do we
#have to account for speed of the earth.... This can be a very complex
#simple complex problem. And the arc continues onward through the arc.
#So spin continues.
#
#Simply if the bullet arcs it does as you say. 99.99999999% are like that!
#
#If the odd perfect shot where in theory it stalls and noses over,
#I suspect the spin starts in the fall.
#
#We get into metal types and teh land cuts on the bullet so much to
#figure with. How about north / south of the equator...
#
#Enough to make a person nuts just thinking.
#
#Martin

In most of the test shots over the decades...bullets tend to land base
first when fired upwards.
TimR
2016-06-15 20:13:15 UTC
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On Wednesday, June 15, 2016 at 7:12:18 AM UTC-4, Martin Eastburn wrote:

#=20
# If the odd perfect shot where in theory it stalls and noses over,
# I suspect the spin starts in the fall.
#=20

I don't think so.

If it's an absolutely perfect straight up shot, two things can happen.

It can have no spin, in which case it will fall base forward, because that's
where the center of mass is.

It can have sufficient spin to stabilize it, in which case it will also fall
base forward, because the spin will keep the nose up.

It's the arcing shots that might be different. Enough spin, it will continue
nose forward; less spin, it will rotate to base forward. I've seen enough
oblong holes on targets to know not all bullets have enough spin. The slower
the projectile, the more spin it needs. (also the longer the projectile)
Joe Pfeiffer
2016-06-16 00:03:57 UTC
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TimR <***@aol.com> writes:

# On Tuesday, June 14, 2016 at 9:18:08 PM UTC-4, Peter Franks wrote:
# # On 2/22/2016 2:28 AM, Martin Eastburn wrote:
# # # When you shoot up gravity and air pressure retard the bullet. The
# # # bullet comes to zero speed and does a nose over.
# #
# # Won't nose over due to gyroscopic effect due to rotation. A bullet may
# # be spinning at 120,000 RPM out of the barrel, and will be still spinning
# # by the time it hits whatever it hits.
# #
# .
#
# I'm pretty sure a falling bullet without spin will stabilize base
# first. It's a mass stabilized projectile at that point. The center
# of mass is near the base.
#
# It is likely impossible to shoot a bullet absolutely straight, so I
# think as long as spin remains, a bullet will travel nose first in an
# arc, both on the way up and the way down.

To the extent that it is spin stabilized, it won't change orientation.
Peter Franks
2016-06-16 00:03:58 UTC
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On 6/15/2016 1:13 PM, TimR wrote:
# On Tuesday, June 14, 2016 at 9:18:08 PM UTC-4, Peter Franks wrote: #
# On 2/22/2016 2:28 AM, Martin Eastburn wrote: # # When you shoot up
# gravity and air pressure retard the bullet. The # # bullet comes to
# zero speed and does a nose over. # # Won't nose over due to
# gyroscopic effect due to rotation. A bullet may # be spinning at
# 120,000 RPM out of the barrel, and will be still spinning # by the
# time it hits whatever it hits. # .
#
# I'm pretty sure a falling bullet without spin will stabilize base
# first. It's a mass stabilized projectile at that point. The center
# of mass is near the base.

May be, either way, it won't 'nose over' as the OP suggested.

# It is likely impossible to shoot a bullet absolutely straight, so I
# think as long as spin remains, a bullet will travel nose first in an
# arc, both on the way up and the way down.

I don't know about that. Fairly easy to empirically disprove that. I'm
presuming you are older and remember those 'wizzer' top toys (gyroscopic
top). Spin one up, and point the nose up. Now, while holding the top,
move it in an arc (up and then down), does the gyroscopic tendency keep
the nose pointed in the direction of travel, or the original
orientation? The latter, ergo I presume that a bullet would behave the
same way: shot in an arc, it will 'keyhole' upon landing (presuming air
resistance is less than gyroscopic effect).

# However I have seen oblong holes in targets, so it is evident that
# some bullets do not have sufficient spin to travel nose first, and
# slower bullets would be more affected by this.

Keyholing at the standard target distances is typically due to improper
spin rate (i.e. wrong rifling twist) for the bullet characteristics.
Martin Eastburn
2016-06-16 10:23:14 UTC
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That sounds logical.
Base is normally higher density over the wide area.
Martin
Martin Eastburn
2016-06-16 10:23:15 UTC
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Arc's by definition is a continuous flow of the same trajectory. Arrows
continue flight in the arc and they are long. The bullet just continues
as it heads down always under power.

If it stalls out then the base pulls it down. But winds jack with it
and anything could happen, but the base likely wins having the center of
gravity well back from the nose.

Martin
Gunner Asch
2016-06-16 12:11:38 UTC
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On Thu, 16 Jun 2016 10:23:15 +0000 (UTC), Martin Eastburn
<***@consolidated.net> wrote:

#Arc's by definition is a continuous flow of the same trajectory. Arrows
#continue flight in the arc and they are long. The bullet just continues
#as it heads down always under power.
#
#If it stalls out then the base pulls it down. But winds jack with it
#and anything could happen, but the base likely wins having the center of
#gravity well back from the nose.
#
#Martin

Dont forget that the bullet is still spinning. While forward motion
has slowed..rotational spin hasnt slowed down much....
TimR
2016-06-16 16:18:25 UTC
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On Thursday, June 16, 2016 at 6:23:17 AM UTC-4, Martin Eastburn wrote:
# Arc's by definition is a continuous flow of the same trajectory. Arrows
# continue flight in the arc and they are long. The bullet just continues
=20
# as it heads down always under power.

I've shot arrows straight up. They stop, fall back feathers first a few feet,
then flip around. They are fin stabilized as opposed to mass stabilized, but
the same thing would happen to a bullet that is either a) not spinning, very
unlikely unless shot from a smoothbore, or b) not spinning fast enough.

b) is far from impossible. A lot of bullets are marginal, and the spin might
decrease enough during flight that it's no longer sufficient for a long slow
(very slow) bullet.
Joe Pfeiffer
2016-06-16 13:58:38 UTC
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Martin Eastburn <***@consolidated.net> writes:

# That sounds logical.
# Base is normally higher density over the wide area.
# Martin

How is the base's density going to be any different than the rest? It's
all lead (I doubt that in a jacketed projectile the jacket makes a
significant difference).
Don Bruder
2016-06-16 18:01:54 UTC
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In article <njubae$efo$***@news.albasani.net>,
Joe Pfeiffer <***@cs.nmsu.edu> wrote:

# Martin Eastburn <***@consolidated.net> writes:
#
# # That sounds logical.
# # Base is normally higher density over the wide area.
# # Martin
#
# How is the base's density going to be any different than the rest? It's
# all lead (I doubt that in a jacketed projectile the jacket makes a
# significant difference).

It's not so much the density of the material as where the material is
located. Think about it: Take a bullet - ANY bullet - and use whatever
method suits you to cut an eighth of an inch off the tip end of it, and
an eighth of an inch off the base end. Which of the two chunks weighs
more? If it isn't a perfectly cylindrical "wadcutter" bullet, the chunk
you take off the base is all but guaranteed to be heavier than the chunk
from the tip. (Certain "weird" bullet shapes - hollow or "cupped"
boat-tail designs come to mind - might be an exception) From this you
can easily figure out that in the vast majority of cases, there's more
material in the base of a bullet than in the tip. Which is the whole
point of spin-stabilizing the bullet with rifling - Without it, the more
massive back end of the bullet wants to swap places with the less
massive front end in flight.
--
Brought to you by the letter Q and the number .357
Security provided by Horace S. & Dan W.
Joe Pfeiffer
2016-06-16 13:58:40 UTC
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Martin Eastburn <***@consolidated.net> writes:

# Arc's by definition is a continuous flow of the same trajectory. Arrows
# continue flight in the arc and they are long. The bullet just continues
# as it heads down always under power.
#
# If it stalls out then the base pulls it down. But winds jack with it
# and anything could happen, but the base likely wins having the center of
# gravity well back from the nose.

It's following a ballistic trajectory, it isn't flying by aerodynamics.
It can't stall. And the whole bullet pulls it down, not just the base.
TimR
2016-10-11 19:56:25 UTC
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On Sunday, October 9, 2016 at 7:49:15 PM UTC-4, AUGOLDMINER wrote:

#
# i got to talking to a couple old guys that did weapons testing at NOTS China
# Lake Calif and found that if you shoot a gun near straight up the bullet
# will go up till it runs out of speed then because of gyroscopic action it will
# fall base down till it hits the ground.
#

That may or may not be true.

However, if you shoot a gun straight up with no spin at all, it will still stabilize base down on the way down. Base first is stable because of aerodynamics without any spin effects.
Peter Franks
2016-10-16 13:16:15 UTC
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On 10/9/2016 4:49 PM, AUGOLDMINER wrote:
# i use to go to mud dry lake in NV ...

Which dry lake?

R.L. Horn
2016-02-23 02:24:39 UTC
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On Mon, 22 Feb 2016 21:17:33 +0000 (UTC), Joe Pfeiffer
<***@cs.nmsu.edu> wrote:

# We all hear about "this can happen", but I don't know when I've ever
# actually read about a case that involved a near-vertical bullet coming
# down and hurting someone.

You don't see people firing guns vertically, do you? I suspect it has
something to do with the fact that, if you ask someone to look "straight
up," few will lean back and actually look straight up.

There's also a certain selfish rationale there as it reduces the,
already almost zero, chance of conking yourself on the head to zero.

Where I live, many now eschew shooting into the air in favor of shooting
into Tannerite. On the one hand it's annoying as hell but, on the
other, at least they're shooting at *something* (I can tell you from
experience that a .22LR can penetrate aluminum siding from some
considerable distance).
Murff
2016-06-15 20:13:17 UTC
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On Wed, 15 Jun 2016 11:12:16 +0000, Martin Eastburn wrote:

# I think if an arc is shot - who can shoot 90 degrees upwards - do we
# have to account for speed of the earth.... This can be a very complex
# simple complex problem. And the arc continues onward through the arc.
# So spin continues.

Not exactly guns you can "tote yourself", but AIUI old-fashioned big
naval guns needed to be able do this due to time-of-flight being
significant (then again, the lead needed when shooting at a moving target
is more significant).

Similarly, I remember the reticle etched into the backup optical sight on
the main gun of a Challenger tank. This includes a representation of the
shot trajectory, and it is curved (unlike the M1 series and the German
Leopard, which use 120mm smooth-bore guns, the Challenger has a 120mm
rifled gun which gives more flexibility in ammunition selection).
--
Murff...
R.L. Horn
2016-06-16 13:08:03 UTC
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Raw Message
On Wed, 15 Jun 2016 20:13:17 +0000 (UTC), Murff <***@warlock.org>
wrote:

# Not exactly guns you can "tote yourself", but AIUI old-fashioned big
# naval guns needed to be able do this due to time-of-flight being
# significant

Hey, not all *that* old-fashioned. Missouri and Wisconsin (not to
mention their destroyer companions) were hurling shells at Iraqi
positions only 25 years ago. Granted, it was pretty much their swan
song...at least until the board-game aliens attack again.
the_shadow
2016-07-04 00:33:39 UTC
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Raw Message
On 2016-06-16, Martin Eastburn <***@consolidated.net> wrote:
# Arc's by definition is a continuous flow of the same trajectory. Arrows
# continue flight in the arc and they are long. The bullet just continues
# as it heads down always under power.

How is it always under power?
--
Bob Holtzman
Just Wondering
2016-07-04 11:16:27 UTC
Permalink
Raw Message
On 7/3/2016 6:33 PM, the_shadow wrote:
# On 2016-06-16, Martin Eastburn <***@consolidated.net> wrote:
# # Arc's by definition is a continuous flow of the same trajectory. Arrows
# # continue flight in the arc and they are long. The bullet just continues
# # as it heads down always under power.
#
# How is it always under power?
#
Maybe he means always subject to external forces?
Gunner Asch
2016-07-04 11:16:30 UTC
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Raw Message
On Mon, 4 Jul 2016 00:33:39 +0000 (UTC), the_shadow
<***@xcoxx.net> wrote:

#On 2016-06-16, Martin Eastburn <***@consolidated.net> wrote:
## Arc's by definition is a continuous flow of the same trajectory. Arrows
## continue flight in the arc and they are long. The bullet just continues
## as it heads down always under power.
#
#How is it always under power?

And the begginning and ends of that arc are Dramatically different
the_shadow
2016-07-09 19:58:22 UTC
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Raw Message
On 2016-07-04, Just Wondering <***@comcast.net> wrote:
# On 7/3/2016 6:33 PM, the_shadow wrote:
# # On 2016-06-16, Martin Eastburn <***@consolidated.net> wrote:
# # # Arc's by definition is a continuous flow of the same trajectory. Arrows
# # # continue flight in the arc and they are long. The bullet just continues
# # # as it heads down always under power.
# #
# # How is it always under power?
# #
# Maybe he means always subject to external forces?

Maybe, but not being a mind reader I can't say what he meant. I only
know what he said.
--
Bob Holtzman
Martin Eastburn
2016-07-10 10:45:03 UTC
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On the way up, pressures in the barrel push against it and yourself and
the bullet takes on the force and flies out of the barrel. It hits the
top of the Arc or straight line if precision gunning is done, it then
stalls and starts to fall. Gravity pulls on it in ever increasing
speed. The bullet is at terminal velocity when it lands on the surface
of the earth or impact point.

Going up is powder and coming down is G force. The bullet doesn't float
around once on the top, doesn't drift down like a leaf.

Martin
Joe Pfeiffer
2016-07-10 23:18:47 UTC
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Raw Message
Martin Eastburn <***@consolidated.net> writes:

# On the way up, pressures in the barrel push against it and yourself and
# the bullet takes on the force and flies out of the barrel. It hits the
# top of the Arc or straight line if precision gunning is done, it then
# stalls and starts to fall. Gravity pulls on it in ever increasing
# speed. The bullet is at terminal velocity when it lands on the surface
# of the earth or impact point.
#
# Going up is powder and coming down is G force. The bullet doesn't float
# around once on the top, doesn't drift down like a leaf.

And... no. Newton is the guy who figured out that this isn't how forces
and momentum work.

The force from pressure ends the moment the bullet leaves the barrel.
It doesn't "take on the force", it has momentum in the particular
direction it's moving when it leaves.

Once it's out of the barrel, air drag slows it down. No matter what
direction it's going at the moment, air drag is acting against that
direction of travel.

Gravity is pulling it down at all times -- even while it's still in the
barrel. It does this with a constant force until the bullet is on the
ground (at which point it's actually still pulling it down, but now the
upward force of the ground balances it).

It never stalls; that's purely an aerodynamic effect on something that
has aerodynamic lift -- a bullet has no significant lift.

It never travels in a straight line. It's always in an arc, from the
moment it leaves the barrel.

Terminal velocity is when it's going straight down and air drag is
balancing gravity (and it won't ever be going *quite* straight down, but
it'll be close enough for this discussion). It's got nothing to do with
how fast it's going when it hits the ground.
Martin Eastburn
2016-07-11 10:26:03 UTC
Permalink
Raw Message
On 7/10/2016 6:18 PM, Joe Pfeiffer wrote:
# Martin Eastburn <***@consolidated.net> writes:
#
# # On the way up, pressures in the barrel push against it and yourself and
# # the bullet takes on the force and flies out of the barrel. It hits the
# # top of the Arc or straight line if precision gunning is done, it then
# # stalls and starts to fall. Gravity pulls on it in ever increasing
# # speed. The bullet is at terminal velocity when it lands on the surface
# # of the earth or impact point.
# #
# # Going up is powder and coming down is G force. The bullet doesn't float
# # around once on the top, doesn't drift down like a leaf.
#
# And... no. Newton is the guy who figured out that this isn't how forces
# and momentum work.
#
Good ole Newton knew a lot of things, but he is behind the apple now.
But his old rules and then some apply.

# The force from pressure ends the moment the bullet leaves the barrel.
# It doesn't "take on the force", it has momentum in the particular
# direction it's moving when it leaves.

And you didn't read or understand.
#
# Once it's out of the barrel, air drag slows it down. No matter what
# direction it's going at the moment, air drag is acting against that
# direction of travel.
#
# Gravity is pulling it down at all times -- even while it's still in the
# barrel. It does this with a constant force until the bullet is on the
# ground (at which point it's actually still pulling it down, but now the
# upward force of the ground balances it).
#
Who said to shoot it parallel to the ground at a target ?

# It never stalls; that's purely an aerodynamic effect on something that
# has aerodynamic lift -- a bullet has no significant lift.
#
Never said it was a flying wing. No wing lift.
Going up until the losses to forward motion overcome the forward and
then the forces of pulling it back take over.

# It never travels in a straight line. It's always in an arc, from the
# moment it leaves the barrel.
#
It depends on the angle the barrel is pointed.

# Terminal velocity is when it's going straight down and air drag is
# balancing gravity (and it won't ever be going *quite* straight down, but
# it'll be close enough for this discussion). It's got nothing to do with
# how fast it's going when it hits the ground.
#
The air drag, wind and everything else retards the fall to a set value
called Term Velocity. It can't go faster. Just like you falling from a
100 story building - you hit Term vel yourself. Anything does - there
are complex formulae for that.

Martin
TimR
2016-07-11 16:41:39 UTC
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Raw Message
On Monday, July 11, 2016 at 6:26:06 AM UTC-4, Martin Eastburn wrote:
# # It never travels in a straight line. It's always in an arc, from the
# # moment it leaves the barrel.
# #
# It depends on the angle the barrel is pointed.
#


Joe, you're 100% right on everything else, but Martin's got you on this one.

It DOES depend on the angle the barrel is pointed.

If the barrel is pointed straight down, no arc.

If the barrel is pointed in any other direction there will be an arc.
Joe Pfeiffer
2016-07-11 16:41:38 UTC
Permalink
Raw Message
Martin Eastburn <***@consolidated.net> writes:

# On 7/10/2016 6:18 PM, Joe Pfeiffer wrote:
# # Martin Eastburn <***@consolidated.net> writes:
# #
# # # On the way up, pressures in the barrel push against it and yourself and
# # # the bullet takes on the force and flies out of the barrel. It hits the
# # # top of the Arc or straight line if precision gunning is done, it then
# # # stalls and starts to fall. Gravity pulls on it in ever increasing
# # # speed. The bullet is at terminal velocity when it lands on the surface
# # # of the earth or impact point.
# # #
# # # Going up is powder and coming down is G force. The bullet doesn't float
# # # around once on the top, doesn't drift down like a leaf.
# #
# # And... no. Newton is the guy who figured out that this isn't how forces
# # and momentum work.
# #
# Good ole Newton knew a lot of things, but he is behind the apple now.
# But his old rules and then some apply.
#
# # The force from pressure ends the moment the bullet leaves the barrel.
# # It doesn't "take on the force", it has momentum in the particular
# # direction it's moving when it leaves.
#
# And you didn't read or understand.

You said "On the way up, pressures in the barrel push against it and
yourself and the bullet takes on the force and flies out of the
barrel." Is that not what you meant?

# # Once it's out of the barrel, air drag slows it down. No matter what
# # direction it's going at the moment, air drag is acting against that
# # direction of travel.
# #
# # Gravity is pulling it down at all times -- even while it's still in the
# # barrel. It does this with a constant force until the bullet is on the
# # ground (at which point it's actually still pulling it down, but now the
# # upward force of the ground balances it).
# #
# Who said to shoot it parallel to the ground at a target ?

You said "It hits the top of the Arc or straight line if precision
gunning is done," No, it's never in a straight line.

# # It never stalls; that's purely an aerodynamic effect on something that
# # has aerodynamic lift -- a bullet has no significant lift.
# #
# Never said it was a flying wing. No wing lift.

You said "it then stalls and starts to fall." It can only stall if it
has lift.

# Going up until the losses to forward motion overcome the forward and
# then the forces of pulling it back take over.

# # It never travels in a straight line. It's always in an arc, from the
# # moment it leaves the barrel.
# #
# It depends on the angle the barrel is pointed.

OK, straight up or down are special cases. Except for those cases, it's
an arc.

# # Terminal velocity is when it's going straight down and air drag is
# # balancing gravity (and it won't ever be going *quite* straight down, but
# # it'll be close enough for this discussion). It's got nothing to do with
# # how fast it's going when it hits the ground.
# #
# The air drag, wind and everything else retards the fall to a set value
# called Term Velocity. It can't go faster. Just like you falling from a
# 100 story building - you hit Term vel yourself. Anything does - there
# are complex formulae for that.

They aren't terribly complicated. And you said "The bullet is at
terminal velocity when it lands on the surface of the earth or impact
point." And, well, not necessarily.

Look, I can only respond to what you write, and what you write has very
little to do with real physics.
Just Wondering
2016-07-11 19:59:05 UTC
Permalink
Raw Message
On 7/11/2016 10:41 AM, TimR wrote:
# On Monday, July 11, 2016 at 6:26:06 AM UTC-4, Martin Eastburn wrote:
# # # It never travels in a straight line. It's always in an arc, from the
# # # moment it leaves the barrel.
# # It depends on the angle the barrel is pointed.
#
# Joe, you're 100% right on everything else, but Martin's got you on this one.
# It DOES depend on the angle the barrel is pointed.
# If the barrel is pointed straight down, no arc.
# If the barrel is pointed in any other direction there will be an arc.
#
If you want to get THAT technical, pointing the barrel straight down
will also result in an arc, due to the Coriolis effect. A very small
arc to be sure, but an arc just the same.
TimR
2016-07-11 21:38:01 UTC
Permalink
Raw Message
On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Just Wondering wrote:
# If you want to get THAT technical, pointing the barrel straight down=20
# will also result in an arc, due to the Coriolis effect. A very small=20
# arc to be sure, but an arc just the same.

Yeah, I did think about that, but decided to overlook it. This would be very
small shooting down, but exaggerated shooting up, I would think.

On the other hand, isn't the Coriolis caused by the earth's rotation? If so,
it would depend on frame of reference, no? A side view from a person attached
to and rotating with the earth would see the bullet arcing from East to West.
However if the barrel were the coordinate axis, wouldn't the path be straight?
Relative to the barrel?
Joe Pfeiffer
2016-07-11 19:59:07 UTC
Permalink
Raw Message
TimR <***@aol.com> writes:

# On Monday, July 11, 2016 at 6:26:06 AM UTC-4, Martin Eastburn wrote:
# # # It never travels in a straight line. It's always in an arc, from the
# # # moment it leaves the barrel.
# # #
# # It depends on the angle the barrel is pointed.
# #
#
#
# Joe, you're 100% right on everything else, but Martin's got you on this one.
#
# It DOES depend on the angle the barrel is pointed.
#
# If the barrel is pointed straight down, no arc.
#
# If the barrel is pointed in any other direction there will be an arc.

Yes, you're right (I acknowledged that in my next post). He was talking
about "precision gunning" being in a straight line instead of an arc,
so I wrote too quickly.
TimR
2016-07-11 21:38:03 UTC
Permalink
Raw Message
On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Joe Pfeiffer wrote:
# TimR <***@aol.com> writes:
#
# # On Monday, July 11, 2016 at 6:26:06 AM UTC-4, Martin Eastburn wrote:
# # # # It never travels in a straight line. It's always in an arc, from the
# # # # moment it leaves the barrel.
# # # #
# # # It depends on the angle the barrel is pointed.
# # #
# #
# #
# # Joe, you're 100% right on everything else, but Martin's got you on this one.
# #
# # It DOES depend on the angle the barrel is pointed.
# #
# # If the barrel is pointed straight down, no arc.
# #
# # If the barrel is pointed in any other direction there will be an arc.
#
# Yes, you're right (I acknowledged that in my next post). He was talking
# about "precision gunning" being in a straight line instead of an arc,
# so I wrote too quickly.

I don't even think a laser is a straight line; refraction from different temperatures
along the path cause it to bend. It would sure solve range estimation problems though.
Gunner Asch
2016-07-12 09:40:33 UTC
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Raw Message
On Mon, 11 Jul 2016 21:38:03 +0000 (UTC), TimR <***@aol.com>
wrote:

#On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Joe Pfeiffer wrote:
## TimR <***@aol.com> writes:
##
## # On Monday, July 11, 2016 at 6:26:06 AM UTC-4, Martin Eastburn wrote:
## # # # It never travels in a straight line. It's always in an arc, from the
## # # # moment it leaves the barrel.
## # # #
## # # It depends on the angle the barrel is pointed.
## # #
## #
## #
## # Joe, you're 100% right on everything else, but Martin's got you on this one.
## #
## # It DOES depend on the angle the barrel is pointed.
## #
## # If the barrel is pointed straight down, no arc.
## #
## # If the barrel is pointed in any other direction there will be an arc.
##
## Yes, you're right (I acknowledged that in my next post). He was talking
## about "precision gunning" being in a straight line instead of an arc,
## so I wrote too quickly.
#
#I don't even think a laser is a straight line; refraction from different temperatures
#along the path cause it to bend. It would sure solve range estimation problems though.
#
And bullets, ..some bullets..do generate Lift..which is one of the
reasons certain bullet shapes are far better at longer ranges..they
spin and go slightly nose up, depending on shape, spin rate length,
and velocity

http://www.throwinglead.com/index.php?page=ballistics_external
Just Wondering
2016-07-12 00:58:56 UTC
Permalink
Raw Message
On 7/11/2016 3:38 PM, TimR wrote:
# On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Just Wondering wrote:
# # If you want to get THAT technical, pointing the barrel straight down=20
# # will also result in an arc, due to the Coriolis effect. A very small=20
# # arc to be sure, but an arc just the same.
#
# Yeah, I did think about that, but decided to overlook it. This would be very
# small shooting down, but exaggerated shooting up, I would think.
#
# On the other hand, isn't the Coriolis caused by the earth's rotation? If so,
# it would depend on frame of reference, no? A side view from a person attached
# to and rotating with the earth would see the bullet arcing from East to West.
# However if the barrel were the coordinate axis, wouldn't the path be straight?
# Relative to the barrel?
#
Sorry, I was really nitpicking; I rather expect the arc would be
imperceptible. But if you want to envision it, start by imagining
dropping a bowling ball from a resting position two miles up. In the
seconds before landfall, the earth would have rotated relative to the
ball (no, I'm not going to calculate how far), resulting in a curve that
would be observable to someone looking perpendicular to the direction of
the earth's rotation, not so much to someone looking in the direction of
the earth's rotation.
TimR
2016-07-12 09:40:38 UTC
Permalink
Raw Message
On Monday, July 11, 2016 at 8:58:59 PM UTC-4, Just Wondering wrote:
# On 7/11/2016 3:38 PM, TimR wrote:
# # On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Just Wondering wrote:
# # # If you want to get THAT technical, pointing the barrel straight down=20
# # # will also result in an arc, due to the Coriolis effect. A very small=20
# # # arc to be sure, but an arc just the same.
# #
# # Yeah, I did think about that, but decided to overlook it. This would be very
# # small shooting down, but exaggerated shooting up, I would think.
# #
# # On the other hand, isn't the Coriolis caused by the earth's rotation? If so,
# # it would depend on frame of reference, no? A side view from a person attached
# # to and rotating with the earth would see the bullet arcing from East to West.
# # However if the barrel were the coordinate axis, wouldn't the path be straight?
# # Relative to the barrel?
# #
# Sorry, I was really nitpicking; I rather expect the arc would be
# imperceptible. But if you want to envision it, start by imagining
# dropping a bowling ball from a resting position two miles up. In the
# seconds before landfall, the earth would have rotated relative to the
# ball (no, I'm not going to calculate how far), resulting in a curve that
# would be observable to someone looking perpendicular to the direction of
# the earth's rotation, not so much to someone looking in the direction of
# the earth's rotation.

I think the effect is not negligible with artillery.
Gunner Asch
2016-07-12 09:40:39 UTC
Permalink
Raw Message
On Tue, 12 Jul 2016 00:58:56 +0000 (UTC), Just Wondering
<***@comcast.net> wrote:

#On 7/11/2016 3:38 PM, TimR wrote:
## On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Just Wondering wrote:
## # If you want to get THAT technical, pointing the barrel straight down=20
## # will also result in an arc, due to the Coriolis effect. A very small=20
## # arc to be sure, but an arc just the same.
##
## Yeah, I did think about that, but decided to overlook it. This would be very
## small shooting down, but exaggerated shooting up, I would think.
##
## On the other hand, isn't the Coriolis caused by the earth's rotation? If so,
## it would depend on frame of reference, no? A side view from a person attached
## to and rotating with the earth would see the bullet arcing from East to West.
## However if the barrel were the coordinate axis, wouldn't the path be straight?
## Relative to the barrel?
##
#Sorry, I was really nitpicking; I rather expect the arc would be
#imperceptible. But if you want to envision it, start by imagining
#dropping a bowling ball from a resting position two miles up. In the
#seconds before landfall, the earth would have rotated relative to the
#ball (no, I'm not going to calculate how far), resulting in a curve that
#would be observable to someone looking perpendicular to the direction of
#the earth's rotation, not so much to someone looking in the direction of
#the earth's rotation.

As a side note..that is a very important ingredient in artillery fire
as well. Particularly in naval gun fire. If you are shooting a round
of say..16" diameter and it weighs a ton...you have to plan on the
movement of the earth as to the amount of + or minus lead you have to
use
Joe Pfeiffer
2016-07-12 09:40:36 UTC
Permalink
Raw Message
Just Wondering <***@comcast.net> writes:

# On 7/11/2016 3:38 PM, TimR wrote:
# # On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Just Wondering wrote:
# # # If you want to get THAT technical, pointing the barrel straight down=20
# # # will also result in an arc, due to the Coriolis effect. A very small=20
# # # arc to be sure, but an arc just the same.
# #
# # Yeah, I did think about that, but decided to overlook it. This would be very
# # small shooting down, but exaggerated shooting up, I would think.
# #
# # On the other hand, isn't the Coriolis caused by the earth's rotation? If so,
# # it would depend on frame of reference, no? A side view from a person attached
# # to and rotating with the earth would see the bullet arcing from East to West.
# # However if the barrel were the coordinate axis, wouldn't the path be straight?
# # Relative to the barrel?
# #
# Sorry, I was really nitpicking; I rather expect the arc would be
# imperceptible. But if you want to envision it, start by imagining
# dropping a bowling ball from a resting position two miles up. In the
# seconds before landfall, the earth would have rotated relative to the
# ball (no, I'm not going to calculate how far), resulting in a curve that
# would be observable to someone looking perpendicular to the direction of
# the earth's rotation, not so much to someone looking in the direction of
# the earth's rotation.

And, of course, up where you dropped the bowling ball you're rotating
just slightly faster than the surface of the planet, so it actually
falls slightly ahead (east) of where you'd expect, not slightly behind
(west). But that's a *really* tiny difference.

All about how precise you want to get. First order, just consider a
parabola. Second, add in drag, assuming a constant Cd (and constant
wind speed and direction). Third, consider the actual bullet shape and
the change in drag in flight. Fourth, consider rotation of the earth.
I imagine changes in wind speed and direction over the course of the
flight of the bullet is even tinier than rotation of the earth....
TimR
2016-07-12 13:00:22 UTC
Permalink
Raw Message
On Tuesday, July 12, 2016 at 5:40:35 AM UTC-4, Gunner Asch wrote:
# On Mon, 11 Jul 2016 21:38:03 +0000 (UTC), TimR <***@aol.com>
# wrote:
#
# #On Monday, July 11, 2016 at 3:59:10 PM UTC-4, Joe Pfeiffer wrote:
# ## TimR <***@aol.com> writes:
# ##
# ## # On Monday, July 11, 2016 at 6:26:06 AM UTC-4, Martin Eastburn wrote:
# ## # # # It never travels in a straight line. It's always in an arc, from the
# ## # # # moment it leaves the barrel.
# ## # # #
# ## # # It depends on the angle the barrel is pointed.
# ## # #
# ## #
# ## #
# ## # Joe, you're 100% right on everything else, but Martin's got you on this one.
# ## #
# ## # It DOES depend on the angle the barrel is pointed.
# ## #
# ## # If the barrel is pointed straight down, no arc.
# ## #
# ## # If the barrel is pointed in any other direction there will be an arc.
# ##
# ## Yes, you're right (I acknowledged that in my next post). He was talking
# ## about "precision gunning" being in a straight line instead of an arc,
# ## so I wrote too quickly.
# #
# #I don't even think a laser is a straight line; refraction from different temperatures
# #along the path cause it to bend. It would sure solve range estimation problems though.
# #
# And bullets, ..some bullets..do generate Lift..which is one of the
# reasons certain bullet shapes are far better at longer ranges..they
# spin and go slightly nose up, depending on shape, spin rate length,
# and velocity
#
# http://www.throwinglead.com/index.php?page=ballistics_external

With round ball, it is possible to deliberately induce lift by imparting backspin (like on a tennis ball.) This is common with paintball and soft air, but has been done with cannons.
Bart B.
2016-08-19 13:33:05 UTC
Permalink
Raw Message
Sierra Bullets' Infinity software calculates their 30 caliber 175-gr. HPMK bullet leaving at
an 80 degree up angle (max usable in their program) going 2600 fps will have a terminal velocity
of 105 fps 3940 yards away horizontally.

If that bullet left at 3000 fps, its terminal velocity will be 245 fps at about 4010 yards
horizontal range.
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