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vapor trails

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Category: Firearms, Bows, and Ammunition
Forum Name: Reloading & Ballistics
Forum Description: Anything to do with ammunition
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Topic: vapor trails
Posted By: Dale Clifford
Subject: vapor trails
Date Posted: February/05/2008 at 17:52
here is a good topic started by someone a while back but not developed, since energy dump was so much fun
besides the condensation from the bullets flight path, there can be seen the actual shock waves --- whats your experience
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=29646#Post29646 - http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=29646#Post29646



Replies:
Posted By: pyro6999
Date Posted: February/05/2008 at 20:33
dale im curious, what exactly is this useful for, im a little lost here

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They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead"

343 we will never forget

God Bless Chris Ledoux
"good ride cowboy"


Posted By: Graysteel
Date Posted: February/05/2008 at 20:46

Leave it to Dale to stir up trouble. :)


When I was in the service we used (and were specifically taught) to use the the vapor trails to assist in spotting round impact. Through 20x optics (typically what the spotter was using) the vapor trail/pressure wave is fairly clear. Some folks would take the scope ever so slightly out of focus (close) as they felt it improved the contrast. To my eye the pressure wave looks sort of like a kids version of a seagull- Sort of dented chevron.




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http://www.whitesounddefense.com/pages/Tech-Articles.html - http://www.whitesounddefense.com/pages/Tech-Articles.html


Posted By: RONK
Date Posted: February/05/2008 at 20:48
 
 It's been a few years since I've shot a thousand yards, and I honestly cannot remember seeing the trace from my own shots, though I think I may have on a few occasions.
 I've seen it vividly, many times as a spotter, standing a few yards behind the shooter, on a warm summer morning with the rising sun behind us. 
  It is absolutely fascinating to watch!
 You pick it up maybe a hundred yards out, watch it arch up to midrange , start it's descent, disappear against the target face, and see the sand splash against the backstop a millisecond after that. IT IS COOL!
 I don't know if it was a vapor trail, shockwave or some sort of an anomoly in the time-space continuum. Hippie
 We just called it "trace".


Posted By: tahqua
Date Posted: February/05/2008 at 20:51
On a humid day you can see the vapor trail of a 22-250 in the first 100yds.


Posted By: pyro6999
Date Posted: February/05/2008 at 20:59
so its just for following the bullet path, not really anything to discuss then? or am i still lost?

-------------
They call me "Boots"
375H&H Mag: Yeah, it kills stuff "extra dead"

343 we will never forget

God Bless Chris Ledoux
"good ride cowboy"


Posted By: Dale Clifford
Date Posted: February/05/2008 at 21:49

it is the physical observation of  most of things under discussion. sometimes the chevrons that graysteel observed look more like a vortex, which is the epilliptic  trace of the traj., or the pitch and yaw. the humidity trace is the one observed most often. if the thermals or heat balloons are moving at 90 deg. in say a 5 mph one can see the shock wave "pop thru the thermal or balloon (for lack of a better word).

in the context of terminal energy probably not to much, but if you've ever seen these shocks  it gives a very intuitive feeling for what it can do to any animal. using 338 and 50's these things are whoppers.  

thermal traces give a real feeling for the slang " boy that load really runs out of gas about 600 yds.".


Posted By: Bigdaddy0381
Date Posted: February/08/2008 at 15:00
On the berger dvd it shows up really well in some of the shots that are taken.
 
It's like watching a Bb being shot from a BB gun but alot faster.It just folds the air around the bullet. cool stuff.
 


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P&Z Firearms , Pro gun cleanings and gun repair and wood refinishing.

Ecclesiastes 10:2



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