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will rain and high humidity.....

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Sparky View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sparky Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 14:25
Originally posted by Kickboxer Kickboxer wrote:

Originally posted by Sparky Sparky wrote:

Originally posted by Rancid Coolaid Rancid Coolaid wrote:



Humidity, like high temperature, decreases air density; and lower air density means less drag on the bullet.



I am not sure I follow you RC. Are you saying that high humidity decreases air density? I would say that high humidity increased air density.

Also someone said if I remember correctly something to the effect that when it is raining it is 100% humidity. That is not correct.

humidity does, in fact, decrease air density... water vapor, humid air (dominated by H20), has lower molecular weight than dry air (dominated by N2 and O2)... since number of molecules is constant, decreased mass in a given volume, therefore, less dense.  


Thanks KB, I think I had a geriatric moment.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 14:28
Just reread this.

To answer you are right it does not have to be 100% humidity for it to rain or it vice versa but if you don't want to put that into your math when you are shooting in a heavy rain don't expect first round hits.

if you are a SWAG shooter please add a full value in rain yes less dense at 100% and therefore the bullet is able to maintain its velocity for a longer period but the rain itself is driving the bullet down and each collision of H2O is causing minute(small) direction changes usually downward to account for as well so a full value must be used every X feet per X feet of rain.  At X distance you loose 1 Mil is your backwards math as all rains are different you have to judge the rain no calculator I know can do this math for you yet...

So shoot calculate loss at x distance than multiply by your final distance your mil of drop for rain.Or when you get to a mil than use that as your variable factor.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 16:20
OR... only shoot in the desert (not in monsoon season)...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rancid Coolaid Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 17:10
Newton was right, frame of reference is very, VERY important.

On the topic of falling bullets: were the barrel to be perfectly parallel to the surface of the earth, the bullet would immediately begin to fall; however, as stated, the barrel is not parallel, it is pointed up - relative to the optical line of sight.

Now, on frame of reference: "falling" is relative to the interactions of 2 specified objects.  The bullet falling to earth is a function of the masses and the distances between the 2.  "Falling" is not the same as "being acted upon by gravitational forces."  As I stated when we did this last time, a geosynchronous satellite is always being pulled toward earth, but is not falling toward earth - meaning the distance between the 2 objects is not diminishing.

So, no additional force need to imparted on the bullet once it has left the muzzle for the bullet to rise; though it is constantly being sucked back toward earth by gravitation, it is not falling toward earth for the entire bullet flight. The "rise" is purely a function of the orientation of the muzzle when the bullets exits.  Point the muzzle straight down and that bullet falls the entire time.  Point it straight up and the bullet does indeed fall part of the time, but only after it has expended all its kinetic energy fighting gravitation, at which time its energy is potential, and gravitation wins.

Gravitation doesn't blow, it sucks!

So...


Edited by Rancid Coolaid - August/15/2013 at 19:58
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 17:51
Rancid you are seemingly talking about two things that are not related...

I really do not believe you can talk about things in space (as that is why it is called or referenced space) and things that are bound by earths constants.

regardless of angle the bullet never rises the trig of it is downward or - so if you want to reference it do so on X and Y.

The "fall" is ridiculous, you are referencing many things in here that are not related, just as you are mistakenly bringing many things kinetic energy, mass, weight, force...

I think that the applied terminology and or definition(s) is/are the issues.

Maybe we can throw the word fall out the window since it has nothing to do with bullets...

Keep it simple:
'propelled object i.e. bullet fired from said rifle in the earths atmosphere under normal conditions (no vacuum, earths gravitational force as experienced by objects on earth), barometric pressure, temp, humidity, altitude, WIND, other environmental conditions and internal and external ballistics effect on bullets impact and translated into terminal ballistics and effect on target (reference to angle of scope and barrel we all understand no one is taking a level shot but are using advanced trig, or impact point is not linear vs point of aim or  POA vs. POI will be at angles"

If we all remember this is where 338 got into a pissing match a long time ago and had to start thinking and call some things into question.  

Where in the world did Fall get into this?  I think I said that already...






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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 17:52
Once again, you are completely wrong and in the wrong frame of reference.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 17:53
ILya PLEASE help us under achievers out over here.  Your use and command of the English language far supersedes any of ours.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 18:19
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 18:23

338 bullets of course.... .80+ BCE
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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 19:28
Guys, I am in Dulles airport with phenomenally slow internet connection, so I am not sure if this post will make it through.

Unlike some super experienced hunters out there, I find terminology to be supremely important.  Words have meaning and precision of expression is superbly important.

The moment the bullet leaves the confines of the barrel it starts accelerating to the local center of mass, which is typically very close to the center of the earth.  The moon does have its effect since it is the second largest mass nearby and depending on the position of the moon, the actual force imparted on the bullet is pointing to some point very close to the center of mass of the Earth, but not exactly coinciding with it.

The word "fall" is not very well defined unless you specify what it is falling with respect to.  The conventional usage of the word fall refers to falling with respect to the Earth, so if the bullet was fired upwards, it will not start falling until it reaches its highest point.

However, if you specify a specific frame of reference, you can say that it is always falling.  For example, it is always falling with respect to the bore axis (unless you have a pencil barrel rifle the whip of which can screw that up too).

When you consider the instant when the bullet leaves the barrel keep in mind that the muzzle can in fact be pointed somewhat upward when it releases the bullet, depending on the specific barrel harmonics.

As far as the rain and humidity go, humidity decreases air density.  Rain introduces particles.  Two different effects.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 19:37
LOUD AND CLEAR THANK YOU 

ILya...

It is the particulate matter mass that I am referring too...  To Original Poster as per the intro to the ???'s

"was wondering if rain, low temperatures and high humidity have any effect on bullet speed..does it cause drag or does the bullet and its shockwave clear a path..."
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 19:40
I never said Fall (I don't believe I did)...Wait uhm... I tried to mis quote you and said it...

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rancid Coolaid Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 20:03
First and foremost, I pulled a Raider, for which I am supremely sorry - I made a HUGE mistake, I meant parallel but put in perpendicular, and that probably caused MUCH of the confusion.

Having cleared that up, ILya said basically the same thing I did, and we are right and everyone else is wrong! Wrong as 2 boys in bed!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 338LAPUASLAP Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 20:05
i need more than that...


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Post Options Post Options   Thanks (0) Thanks(0)   Quote koshkin Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 20:14
Originally posted by 338LAPUASLAP 338LAPUASLAP wrote:

LOUD AND CLEAR THANK YOU 

ILya...

It is the particulate matter mass that I am referring too...  To Original Poster as per the intro to the ???'s

"was wondering if rain, low temperatures and high humidity have any effect on bullet speed..does it cause drag or does the bullet and its shockwave clear a path..."
 
Make a distinction between gases and liquids. Rain introduces non-gaseous particles into the air. Humidity simply changes the gas mixture.
Shockwave business is a little complicated. In supersonic flight the projectile's shockwave largely trails the projectile.
Then there is the effect of superheated ionized surrounding the projectile and evaporating things.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sparky Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 20:19
Originally posted by koshkin koshkin wrote:


Unlike some super experienced hunters out there, I find terminology to be supremely important.  Words have meaning and precision of expression is superbly important.



Well said!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: August/15/2013 at 21:36
Here is what Hornady has to say about it:


NOTE: especially the part that says:
"The firearm's barrel is elevated. The axis of the bore becomes the line of departure for a bullet leaving its muzzle. So rapidly do gravity and air resistance come into play that the bullet departure line is tangent to the trajectory only at the muzzle. The trajectory immediately begins to drop below the bore axis. "

It has nothing to do with what anyone "thinks", the laws of physics are pretty well defined.

And, what ILya said is fairly close to what I said, though incomplete.  

Regardless, as soon as the bullet leaves the barrel, it begins to FALL back to earth.  When you put a rocket motor on it, that can change, until then, drag and gravity always win...



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rancid Coolaid Quote  Post ReplyReply Direct Link To This Post Posted: August/16/2013 at 09:53
First, let us define our vocabulary in this particular frame of reference (bullet fired from gun near the surface of the earth.)

1.  Rise: to increase the distance between our bullet and the earth's surface.
2.  Fall: to decrease the distance between our bullet and the earth's surface.
3.  Trajectory: the curved path our bullet takes in flight.
4.  Gravitation: the force of attraction between 2 objects, proportional to their individual masses and the distance between them.


Yes, the trajectory immediately begins to drop below the bore axis, and if that axis were parallel to the earth, the object would indeed begin to fall immediately. However, the bore axis is usually not parallel, and the bullet must rise (relative to the earth's surface) before it begins to fall.

Frame of reference, frame of reference, frame of reference!

If we isolate just these 2 objects, the earth's surface and the bullet, a typical flight involves a portion of rising and a portion of falling, all expending energy, all under the influence of gravitation and drag.

If we agree that the bullet immediately begins falling, then we need a new definition of "falling." 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rancid Coolaid Quote  Post ReplyReply Direct Link To This Post Posted: August/16/2013 at 10:39
Dan, in an effort to not drive you to the loony bin, I went back and re-read your initial post on the matter.  Your frame of reference is bullet and bore, mine has been bullet and earth.

You are absolutely correct: relative to the bore axis, the bullet immediately begins to fall.


And the ship "sailed calmly on."
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tahqua Quote  Post ReplyReply Direct Link To This Post Posted: August/16/2013 at 10:48
I have to go "drop some kids off at the pool" after this one.
Doug
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