casette shifting, again

On Sun, 16 Dec 2018 21:15:00 -0500, Frank Krygowski
wrote:

On 12/16/2018 7:28 PM, John B. Slocomb wrote:


You are ignoring the effect of air resistance which means that the
speed of the projectile decreases with time during it's flight. And,
as the decrease in velocity results in an effective decrease in air
resistance the velocity decrease is not linier from muzzle to target.
For example, taken from a radar generated ballistics table a test
projectile fired at an initial velocity of 2,723 ft/s drops to 2,332
at 300 m, 1981 at 600, 1663 at 900, and 1384 at 1200. The decrease in
velocity and therefore the decrease in drag is 391 ft/s at 300 M, 351
from 300 to 600, 318 from 600 - 900 and 279 from 900 - 1200.

Yep. It's far from simple. If it were, lots more people would be good shots.

:-) Being a good shot has very little or nothing to do with
ballistics :-) More with having a good sight picture, steady hold and
good trigger squeeze :-)

cheers,

John B.

On Sun, 16 Dec 2018 21:34:57 -0500, Frank Krygowski
wrote:

On 12/16/2018 7:38 PM, news18 wrote:
On Sun, 16 Dec 2018 10:54:49 -0600, AMuzi wrote:


Why in the world would anyone want to use Emacs, (by the way the proper
name is "GNU Emacs") an application that is 40 years old. Yes, I know
that it can do many strange and wondrous things but when you get right
down to it, it is hardly the weapon of choice for writing a book,
posting to USENET or keeping one's shopping list current.

Well, John, customers of our s who are 'retired' get amazingly lucrative
offers to rework/rewrite COBOL systems.
Some of the 'obsolete' languages are critically undersupported and in
the case of major bank mainframes, irreplaceable.

When I was younger, I had a semester of Cobol in a degree course, but
never sought work as a cobol programmer. Worse, after having to hack a
few cobol programs to produce extra reports for a company where I was
doing other stuff, I unwisely listed it on my resume as a side skill.
Offers of work flooded in and I quickly emoved any mention. My major
objection was that it was largly the financial sector and I just didn't
want to work in that field.

Yes, companies will pay big money for "obsolete" skills and hardware when
the cost of replacing the program/hardware/system is expensive. I once
sold about 15 ancient Network Interface Cards for about ten times the
price of newer, faster better NICs because their integrated
manufacturing factory relied on these ancient cards for interfacing.

We had an ancient CNC milling machine in one school laboratory. The
machine was in great shape mechanically (school machines accumulate very
few hours compared to industrial ones) but the controller gave more and
more trouble as the years went on. The faculty member who worked with it
had a harder and harder time getting support.

Finally, one time he called with yet another problem, he was told "The
only guy here who knew that controller has died."

A civil engineer that worked for us on one project told me about
working on a job where they wanted to build a wooden bridge.
Apparently the bridge had to support some serious weight and he got
stuck with designing it. Not having ever even thought about wooden
bridges he had no idea where to start. He finally thought that "Hey!
The railroads used to built wooden bridges" and called the railroad
and lo and behold there was still some of the old design data in the
files.

cheers,

John B.

On 12/16/2018 9:57 PM, John B. Slocomb wrote:
On Sun, 16 Dec 2018 21:15:00 -0500, Frank Krygowski
wrote:

On 12/16/2018 7:28 PM, John B. Slocomb wrote:


You are ignoring the effect of air resistance which means that the
speed of the projectile decreases with time during it's flight. And,
as the decrease in velocity results in an effective decrease in air
resistance the velocity decrease is not linier from muzzle to target.
For example, taken from a radar generated ballistics table a test
projectile fired at an initial velocity of 2,723 ft/s drops to 2,332
at 300 m, 1981 at 600, 1663 at 900, and 1384 at 1200. The decrease in
velocity and therefore the decrease in drag is 391 ft/s at 300 M, 351
from 300 to 600, 318 from 600 - 900 and 279 from 900 - 1200.

Yep. It's far from simple. If it were, lots more people would be good shots.

:-) Being a good shot has very little or nothing to do with
ballistics :-) More with having a good sight picture, steady hold and
good trigger squeeze :-)

Depends how far away you are, no?

--
- Frank Krygowski

On 17/12/18 1:57 pm, John B. Slocomb wrote:
On Sun, 16 Dec 2018 21:15:00 -0500, Frank Krygowski
wrote:

On 12/16/2018 7:28 PM, John B. Slocomb wrote:


You are ignoring the effect of air resistance which means that the
speed of the projectile decreases with time during it's flight. And,
as the decrease in velocity results in an effective decrease in air
resistance the velocity decrease is not linier from muzzle to target.
For example, taken from a radar generated ballistics table a test
projectile fired at an initial velocity of 2,723 ft/s drops to 2,332
at 300 m, 1981 at 600, 1663 at 900, and 1384 at 1200. The decrease in
velocity and therefore the decrease in drag is 391 ft/s at 300 M, 351
from 300 to 600, 318 from 600 - 900 and 279 from 900 - 1200.

Yep. It's far from simple. If it were, lots more people would be good shots.

:-) Being a good shot has very little or nothing to do with
ballistics :-) More with having a good sight picture, steady hold and
good trigger squeeze :-)


In addition, I've always found that estimating the distance to a target
is rather critical. Oh, and the wind and how far from aiming generally
horizontal.

--
JS

On Sun, 16 Dec 2018 22:59:23 -0500, Frank Krygowski
wrote:

On 12/16/2018 9:57 PM, John B. Slocomb wrote:
On Sun, 16 Dec 2018 21:15:00 -0500, Frank Krygowski
wrote:

On 12/16/2018 7:28 PM, John B. Slocomb wrote:


You are ignoring the effect of air resistance which means that the
speed of the projectile decreases with time during it's flight. And,
as the decrease in velocity results in an effective decrease in air
resistance the velocity decrease is not linier from muzzle to target.
For example, taken from a radar generated ballistics table a test
projectile fired at an initial velocity of 2,723 ft/s drops to 2,332
at 300 m, 1981 at 600, 1663 at 900, and 1384 at 1200. The decrease in
velocity and therefore the decrease in drag is 391 ft/s at 300 M, 351
from 300 to 600, 318 from 600 - 900 and 279 from 900 - 1200.

Yep. It's far from simple. If it were, lots more people would be good shots.

:-) Being a good shot has very little or nothing to do with
ballistics :-) More with having a good sight picture, steady hold and
good trigger squeeze :-)

Depends how far away you are, no?

Yes, to a certain extent. In the 1,000 yard rifle shooting where a
heavy bullet fired at a high velocity is required ballistics enter
into the equation only to the extent that the average shooter knows
what calibers work best. Or more frankly what doesn't work - the
7.62x51 NATO (.308 Winchester) doesn't work and one of the .300 or
larger magnums works better.

But with all the ballistics in the world, still, the major
requirements are still a firm stance, good sight picture and a good
trigger squeeze.

Ballistics would enter into it in the in the sense of selection of the
correct ammunition for the course of fire. That the ammunition is
constant in muzzle velocity, and accurate in the weapon used - even in
..22 ammunition some makes/lots shoot better than others. The big
military teams, for example, buy large quantities of ammunition and
then test each lot in an enclosed test range.

I once did a little "big bore", i.e., .30 caliber, military match
shooting, 100,200 and 300 yard, and nobody even talked about
ballistics. Other then the basic sight setting was "this" and 200 yds
was 7 clicks up, etc.


cheers,

John B.

On Mon, 17 Dec 2018 15:16:36 +1100, James
wrote:

On 17/12/18 1:57 pm, John B. Slocomb wrote:
On Sun, 16 Dec 2018 21:15:00 -0500, Frank Krygowski
wrote:

On 12/16/2018 7:28 PM, John B. Slocomb wrote:


You are ignoring the effect of air resistance which means that the
speed of the projectile decreases with time during it's flight. And,
as the decrease in velocity results in an effective decrease in air
resistance the velocity decrease is not linier from muzzle to target.
For example, taken from a radar generated ballistics table a test
projectile fired at an initial velocity of 2,723 ft/s drops to 2,332
at 300 m, 1981 at 600, 1663 at 900, and 1384 at 1200. The decrease in
velocity and therefore the decrease in drag is 391 ft/s at 300 M, 351
from 300 to 600, 318 from 600 - 900 and 279 from 900 - 1200.

Yep. It's far from simple. If it were, lots more people would be good shots.

:-) Being a good shot has very little or nothing to do with
ballistics :-) More with having a good sight picture, steady hold and
good trigger squeeze :-)


In addition, I've always found that estimating the distance to a target
is rather critical. Oh, and the wind and how far from aiming generally
horizontal.

I don't know about the present rifles but back in the day when most
1,000 match shooters used either a Springfield or Garand 30-06 on a
windy day the aiming point might be 2 targets to the right and 3
clicks to the left :-)

And even in golf the distance to the target is important :-)

In fact golf and baseball are probably the only two sports where the
players actually think and use ballistics. Possibly also cricket
although I'm not familiar with that sport.

Golfers can, by how they hit the ball, make it curve right or left or
straight and even control the distance the ball rolls after it hits
the ground, to some extent. Baseball pitchers can make the ball do all
kinds of wondrous things by how they hold and release the ball.



cheers,

John B.

On 12/16/2018 4:38 PM, news18 wrote:

snip

Yes, companies will pay big money for "obsolete" skills and hardware when
the cost of replacing the program/hardware/system is expensive. I once
sold about 15 ancient Network Interface Cards for about ten times the
price of newer, faster better NICs because their integrated
manufacturing factory relied on these ancient cards for interfacing.

A couple of months ago I had dinner with a college roommate that I had
not seen for about 30 years. He is a physicist and works at an aerospace
company in Southern California. He is still programming in Fortran.

Speaking of NICs, I worked for the first networking company for personal
computers, before Novell, Corvus, or 3COM. The first cards we built,
before I worked there, were for the Apple II, the Commodore PET, and the
TRS-80. One customer, a school district, came back, long after the Apple
II NICs were discontinued and wanted more Apple II NICs. We told them
that it was an obsolete product and that we had no more. They asked us
"how much to make some" and we quoted them a very high price because we
had no desire to produce more, and they said "okay." We still had the
hand-taped PC board film, and all the components were still available,
so we could build them pretty quickly.

On 12/17/2018 1:20 AM, John B. Slocomb wrote:
On Sun, 16 Dec 2018 22:59:23 -0500, Frank Krygowski
wrote:

On 12/16/2018 9:57 PM, John B. Slocomb wrote:
On Sun, 16 Dec 2018 21:15:00 -0500, Frank Krygowski
wrote:

On 12/16/2018 7:28 PM, John B. Slocomb wrote:


You are ignoring the effect of air resistance which means that the
speed of the projectile decreases with time during it's flight. And,
as the decrease in velocity results in an effective decrease in air
resistance the velocity decrease is not linier from muzzle to target.
For example, taken from a radar generated ballistics table a test
projectile fired at an initial velocity of 2,723 ft/s drops to 2,332
at 300 m, 1981 at 600, 1663 at 900, and 1384 at 1200. The decrease in
velocity and therefore the decrease in drag is 391 ft/s at 300 M, 351
from 300 to 600, 318 from 600 - 900 and 279 from 900 - 1200.

Yep. It's far from simple. If it were, lots more people would be good shots.

:-) Being a good shot has very little or nothing to do with
ballistics :-) More with having a good sight picture, steady hold and
good trigger squeeze :-)

Depends how far away you are, no?

Yes, to a certain extent. In the 1,000 yard rifle shooting where a
heavy bullet fired at a high velocity is required ballistics enter
into the equation only to the extent that the average shooter knows
what calibers work best. Or more frankly what doesn't work - the
7.62x51 NATO (.308 Winchester) doesn't work and one of the .300 or
larger magnums works better.

But with all the ballistics in the world, still, the major
requirements are still a firm stance, good sight picture and a good
trigger squeeze.

Ballistics would enter into it in the in the sense of selection of the
correct ammunition for the course of fire. That the ammunition is
constant in muzzle velocity, and accurate in the weapon used - even in
.22 ammunition some makes/lots shoot better than others. The big
military teams, for example, buy large quantities of ammunition and
then test each lot in an enclosed test range.

I once did a little "big bore", i.e., .30 caliber, military match
shooting, 100,200 and 300 yard, and nobody even talked about
ballistics. Other then the basic sight setting was "this" and 200 yds
was 7 clicks up, etc.

Here's some of what I had in mind:

https://www.longrangehunting.com/thr...results.80403/

https://www.huntinggearguy.com/tips/...range-hunting/

I suppose I shouldn't have said "lots more people." It really applies to
people shooting at relatively long but variable ranges.


--
- Frank Krygowski

On Mon, 17 Dec 2018 07:28:37 +0700, John B. Slocomb
wrote:

Acceleration of gravity = g = 32 ft/sec/sec
Let's say the trajectory height is 100 ft and the range is 1000 ft.
sqrt(height/0.5(g)) = time_of_flight
sqrt(100/0.5(32)) = (10/4) = 2.5 sec
At 1000ft, the muzzle velocity would be 1000/2.5 = 400ft/sec

Or something like that.

You are ignoring the effect of air resistance which means that the
speed of the projectile decreases with time during it's flight. And,
as the decrease in velocity results in an effective decrease in air
resistance the velocity decrease is not linier from muzzle to target.
For example, taken from a radar generated ballistics table a test
projectile fired at an initial velocity of 2,723 ft/s drops to 2,332
at 300 m, 1981 at 600, 1663 at 900, and 1384 at 1200. The decrease in
velocity and therefore the decrease in drag is 391 ft/s at 300 M, 351
from 300 to 600, 318 from 600 - 900 and 279 from 900 - 1200.
:-)

Ok, I yield. Air resistance is significant and can't be ignored.

"Projectile Motion with Air Resistance"
http://farside.ph.utexas.edu/teaching/336k/Newtonhtml/node29.html
We thus conclude that if air resistance is significant
then it causes the horizontal range of the projectile to
scale linearly, rather than quadratically, with the launch
velocity.

Methinks I could use this to produce a tolerable balistic
approximation, which could be used to calculate the muzzle velocity
given the impact velocity at a known distance. However, my math
sucks, I'm still doing battle with two kidney stones, and need to do
some repairs after last nights rain. Thanks for the corrections.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 15 Dec 2018 15:59:21 -0600, AMuzi wrote:

snip

I left school without having slept through even one physics class. My
reference work here is a 1955 high school textbook for $1 (9 Kr). I
don't know all of even that, but I understand the world well enough to
know that this headline last week:

https://www.dailymail.co.uk/sciencet...US-Army-begin-
using-new-automatic-rifles-fire-power-TANK-soon-2022.html

was completely ridiculous. The chamber pressures are in the same range,
but not power, not even within a magnitude*!
Power is work over time. Without some grasp of the actual world, you
would not have laughed aloud when reading the headline, etc.

*A typical 120mm tank round is 7.5 kilos of depleted uranium moving at
1700 m/s. The new 6.8 rifle typically moves 7.5 grams at 850 m/s. That's
why you need basic physics.

There's a reason the Brits call it the "Daily Fail", you know.
--
davethedave