HuntingNut
HuntingNut
   Login or Register
HomeCommunity ForumsPhoto AlbumsRegister
     
 

User Info

Welcome Anonymous


Membership:
Latest: Falcor
New Today: 1
New Yesterday: 1
Overall: 11860

People Online:
Members: 1
Visitors: 42
BOT: 2
Total: 45
Who Is Where:
 Members:
01: slimjim > Forums
 Visitors:
01: Forums
02: Forums
03: Your Account
04: Your Account
05: Forums
06: News
07: Forums
08: Home
09: News
10: Forums
11: News
12: Forums
13: News
14: Forums
15: Your Account
16: Forums
17: Forums
18: Your Account
19: News
20: Forums
21: Forums
22: Forums
23: Forums
24: Forums
25: Home
26: Your Account
27: Forums
28: Forums
29: Your Account
30: Forums
31: News
32: Forums
33: Forums
34: Forums
35: Forums
36: Home
37: Home
38: Forums
39: Forums
40: Forums
41: Forums
42: Forums
  BOT:
01: Photo Albums
02: Forums

Staff Online:

No staff members are online!
 

Coppermine Stats
Photo Albums
 Albums: 306
 Pictures: 2310
  · Views: 222724
  · Votes: 1242
  · Comments: 85
 

Support our Advertisers

Reading mirage...
Discussion that doesnt fit other Topics
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » General

View previous topic :: View next topic  
Author Message
stovepipe
Super Member
Super Member


Joined: Sep 25, 2008
Posts: 4410
Location: Pine, Az.

PostPosted: Wed May 05, 2010 7:36 am    Post subject: Reading mirage... Reply with quote

Last outing I noticed some/a lot of mirage at times. New issue with me since I just started long range w/ glass on my gun.

Just read an interesting article by Gail McMillan on the subject. I had a feelling mirage would affect my POI aiming dead on. Won't say that was the cause of any of my misses last week but it sure is something to think about. I shoot across huge tracts of sun baked hardpan out here and the mirage is really bad at times.

Another interesting tidbit for me to research on this new to me discipline.
Back to top
View user's profile
stovepipe
Super Member
Super Member


Joined: Sep 25, 2008
Posts: 4410
Location: Pine, Az.

PostPosted: Wed May 05, 2010 9:55 am    Post subject: Re: Reading mirage... Reply with quote

Here's the article in case ya need something to read:

The problem of mirage haunts every shooter regardless of experience. Mirage is the culprit when you have a four shot group that looks like one bullet hole and the fifth shot shows up a half inch away. He's the same guy that directs the bullet to the 8 ring when all the rest are in the x ring. There are a lot of wrong ideas about mirage among the different shooting disciplines. Some shooters can ignore it completely; pistol shooters fall into this category. High Power competitors believe it's the wind that does all the damage and mirage is just an indication of which way the wind is blowing, at very long ranges it is a combination of both wind and mirage that affects accuracy. If all you are trying to do is hold 2 minutes of angle you don't need the information that follows. If, on the other hand, you want to shoot better than 1/2 MOA you need to learn to deal with mirage. I am not writing this to put anyone down, I am just reporting what I have learned from nearly a half a century of competition and what has worked for me. If you disagree with me so be it but I am too old to change my ideas and methods so I don't invite arguments.

First what is mirage? To answer that you need to take a glass full of water and put a spoon in it. Look at how the spoon handle appears to bend at the point it enters the water. This is an illusion caused by the difference in the index of refraction of air and water. The variation of air temperature between you and the target causes a change in the index of refraction of the air along your sight path. This bends the light causing the image of the target to be in a different place than the actual target. If you set your rifle in a solid rest, aim it at a target and sit and watch you will see the target appear to dance around under the crosshairs, obviously the target is not moving, it is the image that is moving. What you need to be able to do is determine by watching the mirage where the target is in relation to its image. It is essential that you be able to look at the running mirage and feel confident that you know exactly where the bullet will go when you touch it off. Imagine that you are on the last shot of the match and you have it won going away, time is running out, when conditions switch from lazy right to left mirage to a fast running left to right mirage at a forty five degree angle. You must have confidence in your judgment to hold where you know the target is in relation to the image you are watching and know that your last round will fall in the group. You can't think, "well I think it is over here two inches but I will play it safe and hold one inch". If you do that you are admitting defeat by accepting a one-inch group. You must fully accept the fact that the mirage is moving the image while the target is standing still and go for it.

It is a common fault of young shooters who don't have confidence in their judgment to think that they can wait out conditions and shoot in the same condition each time. It can't be done. It is impossible to remember all of the different variables (position of several wind flags, breeze on the back of your neck, mirage intensity and direction, density of clouds, etc.) for the 5 to 10 minutes it takes to complete a group.

What I hope to accomplish with this article is to tell you the method of training you can use to gain the confidence in your ability to look at a condition and know it is worth x amount and be totally confident that if you hold for the conditions your shot will go right in the group. No one can dope it right every time but it is the champions who get it right the most. Any one with a little practice can look down range and tell the difference in conditions that will cause an inch of difference in the point of impact. To be a champion you must be able to detect a change that will move the point of impact a half a bullet hole.

Step one is to zero your rifle in ideal conditions. That might mean getting up at five in the morning and getting to the range while it is cool and calm and get the rifle to print right beneath the cross hairs. If your scope has adjustable knobs set them at zero so you know where it is hitting under perfect conditions. The next thing you will need is a couple of wind flags. No they are not to tell how much the wind is blowing your bullet. They are to tell you what angle the mirage is running at. The angle the mirage is running has an effect on where it's moving the image. For example the mirage is running at what looks like right to left at a certain speed. You would assume that it is moving the image to the left, which it is, but it may be running at an angle of 40 degrees down range at the same time. Knowing this you can assume it will not be moving the image quite as far to the left as you first thought, also, because it is running away from you it is pushing the image lower. Your challenge is to determine how far to the left and how far up to hold. One old rule is never ever shoot in a boil. That's pretty sound advice but how do you tell a boil from mirage that is running straight away or towards you, the answer, practice. While boiling mirage and running mirage look similar they will cause distinctly different movement of the image, one is raising the image and the other is pushing it down. During this exercise try to pick as many different conditions as possible so that you can learn what each condition will do.

You have a rifle that we know is hitting right under the cross hairs in ideal conditions and hopefully it will shoot ½ moa or better. It's hard to learn much if you can't trust the rifle. You have a good pedestal, sandbag and, if possible, a good spotting scope. A pair of wind flags set up at intervals down range. The afternoon is getting warm and your target frame looks like there are a bunch of mice feet running back and forth on top of it. You have brought a tablet and a pencil to take notes with. You write down the conditions as you see them and then mark where you think the bullet will hit on the target (in the beginning this is just a guess). Now it is time to test your judgment, you take a dead-on hold and fire one round . You look at the target and then at your tablet and see how far you were off and mark your actual impact point in relation to the sketch you drew. Repeat the process again, sketch the target, mark where you think you will hit, load one round, take a dead-on hold and see where you hit. Be sure that you describe the conditions in as much detail as you can. As an example: rt. to lt. at moderate rate wind flag indicates 30 degree down range. It will take a little time to record the conditions, your guess and the actual impact point but this is time well spent, it will give you a chance to study your practice session in the evening and reflect on what you have learned. At this point shooting groups is a waste of time and ammo. Remember not to change your scope from where it was in ideal conditions. You can follow this routine as long as you want or until you are hitting right where you marked every time.

Now you are at the range and are ready to take the nest step. Continue to observe the conditions and make a note of them but instead of taking a dead-on hold from now on you are going to figure where the target really is and hold off of the target image so that you will impact in the x ring. Take a shot and see where you hit. Mark your tablet and repeat. If you are accurate in your reading of the mirage and description of it and you take good notes you will be able to study your notes when you're not at the range and pick up things you might have missed while you were shooting. To make it easier and quicker you can develop a shorthand way to record information, I draw the waves of mirage large and widely spaced for slow mirage and smaller and shorter as the mirage speed increases. The purpose of this exercise is to reinforce your confidence that the mirage is doing what you know it is.

A word about practice, there is a point in practice when it stops accomplishing anything and all you are doing is going through the motions. At this point it is a waste of time and does more harm than good. It is much better to quit while you are fresh and sharp than keep it up until you are past prime. You have proceeded through steps one and two and by now you have a good idea where the target really is under most mirage conditions. It is a good idea to repeat both steps the first thing when getting to the range or when you shoot at a new range as it will reinforce your confidence and in the case of a strange range it will point out any peculiar traits of the range. The saying "hometown advantage" definitely applies to shooting, each range has its own subtle characteristics the homeboys have learned, a little time spent going back to the basics might reduce the "hometown advantage". I will finish this off as though you were going to shoot benchrest competition because it covers shooting groups. By now you are able to judge conditions and you know what is necessary to put the bullet where you want it to go. Now instead of shooting singles you are going to shoot groups. As you probably know in benchrest competition you have a record target and a sighter target. You are allowed unlimited shots on the sighter target and can go back and forth between the record target and sighter target. While you are waiting for the "commence firing" command put the time to good use and study the conditions for as long as you can to determine what the prevailing conditions are.

After the commence fire command wait until the prevailing conditions are running before you start. Shoot your first record shot with a dead-on hold and note where the shot went in relation to the conditions (some rifles require one or more fouling shots before they settle down so it's a good idea to fire a couple of shots into the sighter target first). Remember that you have your bullets printing right under your crosshair so when you fire the first shot it becomes your target, the location of your group in a benchrest match is unimportant so it is not necessary to try to put your first shot in the x ring. Now all you are shooting is a four shot group (because you are shooting at your first shot) while every one else is shooting five. This gives you an advantage right off the start. You watch conditions and determine where the target is (notice I said where the target is, not the image.) If conditions are changing fast you wont have time to go back to your sighter to verify what you think so you will have to go on guts. If the changes are slow then always go back to the sighter when you see a change and verify how much it is worth.

You will notice that I didn't tell you how to read mirage. If I had you wouldn't remember it till you got to the range. I hope I have given you some idea of how to train so that you know how to read it and you will remember it. I can't impress on you the importance in believing that your eyes are lying to you and that the target isn't really where you are seeing it .

There is a small trick that I have used that I will share with you. Your rifle scope is focused at the target and has a very shallow depth of field. That means that you are only seeing the mirage for a few feet at the target. The mirage can be running the opposite direction up range and you will never know it. If you stop down the objective lens by covering it and leaving a small hole in the center you will increase the depth of field and be able to see mirage over a larger area of the range. You can do this by using tape and leaving a hole in the center about the size of a dime.
Back to top
View user's profile
slimjim
Super Member
Super Member


Joined: May 16, 2009
Posts: 5774
Location: Fort Worth TX

PostPosted: Wed May 05, 2010 3:36 pm    Post subject: Re: Reading mirage... Reply with quote

Thanks, stovepipe, for an interesting article.

_________________
"To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt

"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein
Back to top
View user's profile
chambered221
Super Member
Super Member


Joined: Aug 17, 2007
Posts: 3186
Location: Lost for good !!!

PostPosted: Wed May 05, 2010 4:48 pm    Post subject: Re: Reading mirage... Reply with quote

stovey wrote:
There are a lot of wrong ideas about mirage among the different shooting disciplines.

From what little reading I've done on the subject I would agree !!!
Talk to 10 different guys on the subject and I'll bet ya the only thing they agree on is mirage affects POI !!!

_________________
Ask as many people needed, sooner or later your question will be answered the way you want it answered !!!

A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.
~George Washington
Back to top
View user's profile Photo Gallery
stovepipe
Super Member
Super Member


Joined: Sep 25, 2008
Posts: 4410
Location: Pine, Az.

PostPosted: Thu May 06, 2010 6:00 am    Post subject: Re: Reading mirage... Reply with quote

I liked the stopping down trick, kinda like the Merrit device I use for pistols. Was thinking of making a shroud for my barrel but it cools pretty quick. The scopes sun shade helps too...
Back to top
View user's profile
stovepipe
Super Member
Super Member


Joined: Sep 25, 2008
Posts: 4410
Location: Pine, Az.

PostPosted: Thu May 06, 2010 6:18 am    Post subject: Re: Reading mirage... Reply with quote

chambered221 wrote:
stovey wrote:
There are a lot of wrong ideas about mirage among the different shooting disciplines.

From what little reading I've done on the subject I would agree !!!
Talk to 10 different guys on the subject and I'll bet ya the only thing they agree on is mirage affects POI !!!


I found the article interesting. Heavy mirage is a b**h here w/ all this hardpan.

Wanna share some POV? I also think it affects POA more than POI in most cases.
Back to top
View user's profile
Dawgdad
Super Member
Super Member


Joined: Feb 08, 2006
Posts: 892
Location: On the Prairie

PostPosted: Thu May 06, 2010 7:55 am    Post subject: Re: Reading mirage... Reply with quote

In Highpower - I use a spotting scope and pull the focus back off of the target to read mirage. With iron sights it is more useful as a wind reading aid but I mentally account for the image shift by putting on more windage based on the mirage's appearance compared to what the range flags are showing.

_________________
Alcohol, Tobacco and Firearms should be a convenience store, not a government agency...
Back to top
View user's profile Photo Gallery
stovepipe
Super Member
Super Member


Joined: Sep 25, 2008
Posts: 4410
Location: Pine, Az.

PostPosted: Thu May 06, 2010 7:57 am    Post subject: Re: Reading mirage... Reply with quote

Good post dad.
Back to top
View user's profile
chambered221
Super Member
Super Member


Joined: Aug 17, 2007
Posts: 3186
Location: Lost for good !!!

PostPosted: Thu May 06, 2010 5:45 pm    Post subject: Re: Reading mirage... Reply with quote

I found it interesting too !!! I like his approach with hands on learning.

Articles I've read in the past that try to explain what one person sees and how they adjust POA can be downright frustrating.

There are so many variables as to what I see and what you see.
Next time your at the range get someone (w/different scope and magnification) to set up on the same target and get them to explain to you what they see. Does it sound anything like what your seeing ???

One of the biggest reasons I have a variable power scope on my varmint gun is to be able to turn the power down and possibly limit or do away with seeing it.
Sometimes it works ....sometimes it don't.

_________________
Ask as many people needed, sooner or later your question will be answered the way you want it answered !!!

A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.
~George Washington
Back to top
View user's profile Photo Gallery
Donut Slayer
Super Member
Super Member


Joined: Jun 27, 2007
Posts: 578
Location: Pensacola, Florida

PostPosted: Thu May 06, 2010 6:26 pm    Post subject: Re: Reading mirage... Reply with quote

I also think it affects POA more than POI in most cases.

I agree totally. Kinda hard to find the center of the target when it looks like a flag waving in da wind.

_________________
Browning X-Bolt in 30'06. The work for a pet load starts again. Wink The more people I meet, the more I like my dog.
Back to top
View user's profile Send e-mail
Pumpkinslinger
Super Member
Super Member


Joined: Sep 22, 2007
Posts: 3899
Location: NC foothills

PostPosted: Thu May 06, 2010 10:50 pm    Post subject: Re: Reading mirage... Reply with quote

Ah, you just aim at the middle of the blur. That's how I do all my shooting these days! Wink

_________________
Mike

"I ain't no better than anyone else, and there ain't no one better than me!" Ma Kettle

Back to top
View user's profile AIM Address Yahoo Messenger Photo Gallery
stovepipe
Super Member
Super Member


Joined: Sep 25, 2008
Posts: 4410
Location: Pine, Az.

PostPosted: Fri May 07, 2010 6:03 am    Post subject: Re: Reading mirage... Reply with quote

Pumpkinslinger wrote:
Ah, you just aim at the middle of the blur. That's how I do all my shooting these days! Wink

Me too! Laughing
Back to top
View user's profile
Display posts from previous:   
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » General
Page 1 of 1
All times are GMT - 7 Hours



Jump to:  


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Advertisements
 


Valid CSS! Valid HTML 4.01!
Click to check if this page is realy HTML 4.01 compliant for speed :)

All logos and trademarks in this site are property of HuntingNut.com.
The comments are property of their posters, all the rest © 2011 by HuntingNut.com
Interactive software released under GNU GPL, Code Credits, Privacy Policy

.: Upgraded to DragonFly 9.2 by Dizfunkshunal :.