The effects of mirage from barrel

[C. Collins]

I see many people using mirage shields for f and benchrest shooting. How does the mirage from the barrel affect the impression of the down range mirage? Does it just confuse the mirage downrange, giving a false impression of down range mirage? Does it become the dominant mirage presented in the rifle scope? I just don't know. Thank you for your input.

 

[stacy]

IT'S FOR SURE HARD TO SHOOT THE SAME HOLE WHEN THE TARGET IS DOING THE TWO STEP FOR SURE U MUST ALLOW FOR IT

 

[broncman]

It is the dominant mirage in the scope without a mirage shield! People who use a spotting scope to view mirage usually try to focus their spotting scope at the range they want to view the mirage. If they want to foucus on wind say at 700 yards, they pull their focus back from say 1000 and the mirage they see is at the 700 yard range. Some days mirage is so bad it washes out a clear target picture period and you dial your scope power down.

Barrel heat has this effect of and gives no indication of downrange wind... in other words, it makes your target dance with no downrange wind

 

[C. Collins]

I shot last year without a mirage shield. I shot well till about 11-13, then I was hitting low on the target in the 9 ring. This happened consistently at multiple matches. Could this be a result of barrel produced mirage. I would make the adjustment with the scope and then be back to 10's and X's. I thought it was a change in position, but now I am beginning to change my thought. I would use the mirage to judge the conditions down range.

 

[sailhertoo]

Seems like you should have been shooting high.

 

[LCazador]

The mirage coming off your barrel is the dominant mirage and will change or distort the perception of the mirage down range.

 

[watercam]

A rising Mirage will optically displace the target higher than it really is. Hence his low shots...

 

[Erik Cortina]

A rising Mirage will optically displace the target higher than it really is. Hence his low shots...

This would cause you to aim higher, therefore shots would be high, not low.

 

[Steve Blair]

Here is a good article about the effects that mirage has on accuracy. It's from the South Texas Marksmanship Training Center where they probably experience occasional light mirage. [br]
http://southtexasshooting.org/multimedia/text/mirage.html

 

[1shot]

As a lesson taught in class, and learned, sometime the hard way on the range during tactical rifle marksmanship school. "Mirage will always displace the target in the direction of the mirage". End quote; thanks to TGM Major. (retired)
I hope this helps,
Lloyd

 

[Immike]

I see many people using mirage shields for f and benchrest shooting. How does the mirage from the barrel affect the impression of the down range mirage? Does it just confuse the mirage downrange, giving a false impression of down range mirage? Does it become the dominant mirage presented in the rifle scope? I just don't know. Thank you for your input.

Let me throw something out here.. The barrel heat rising in the view of the scope is in just a small area proportional to the field of mirage that has much more distance to bend the light that is displacing the image of the target. My observations (possibly wrong) are that it has little to do with the movement of the target that is documented but makes it hard to see though the masking effects of it. Most experienced shooters use a shield and it's effects are not studied but avoided. Since it is not a constant but a accumulating thing progressive with each shot I recommend getting a mirage shield, lol

 

[mysticplayer]

I shot last year without a mirage shield. I shot well till about 11-13, then I was hitting low on the target in the 9 ring. This happened consistently at multiple matches. Could this be a result of barrel produced mirage. I would make the adjustment with the scope and then be back to 10's and X's. I thought it was a change in position, but now I am beginning to change my thought. I would use the mirage to judge the conditions down range.

Were all the matches that you hit low shot in dead calm air? Odds are no so, I would suggest you have a barrel that warps when it heats up and shoots low.

How to prove. Take an infrared temp gun and measure the barrel temp as you shoot it. Note when the shots start to drop low vs the barrel temp. I bet you will find that the temp when it starts to shoot low is repeatable and if you stop shooting to let it cool, it will return to your orig zero.

Unfortunately, time for a new barrel.

Why the first question about calm air? Because mirage off the barrel reacts to wind the same as the mirage we look at down range.

If you are shooting on a windy day, guess what, the heat off your barrel is also blown down wind.

I didn't bother to use a mirage shield this season and it never was a problem... yes, I did test with and without.

YMMV.

Jerry

 

[Immike]

Several years ago a few of the bench shooters decided to plastic wrap a section of the firing line so they could shoot and test barrels in the winter. They cut a window to shoot through and installed a heater to stay warm. It didn't work with the heat pouring out the window left them unable to see the targets. Lol. Seemed like a good idea.

 

[C. Collins]

I shot last year without a mirage shield. I shot well till about 11-13, then I was hitting low on the target in the 9 ring. This happened consistently at multiple matches. Could this be a result of barrel produced mirage. I would make the adjustment with the scope and then be back to 10's and X's. I thought it was a change in position, but now I am beginning to change my thought. I would use the mirage to judge the conditions down range.

Were all the matches that you hit low shot in dead calm air? Odds are no so, I would suggest you have a barrel that warps when it heats up and shoots low.

How to prove. Take an infrared temp gun and measure the barrel temp as you shoot it. Note when the shots start to drop low vs the barrel temp. I bet you will find that the temp when it starts to shoot low is repeatable and if you stop shooting to let it cool, it will return to your orig zero.

Unfortunately, time for a new barrel.

Why the first question about calm air? Because mirage off the barrel reacts to wind the same as the mirage we look at down range.

If you are shooting on a windy day, guess what, the heat off your barrel is also blown down wind.

I didn't bother to use a mirage shield this season and it never was a problem... yes, I did test with and without.

YM

Jerry

It was windy but no terribly windy. I bought this rifle used, with an unknown round count. It is a 6.5x284, I have put 700 down it since I purchased the rifle. I know a rebarrel is in the near future for this rifle, but I have one in the shop having a new barrel being screwed on already. I want to see how this smith and barrel work before I make any future plans. I am 99% positive that the barrel and smith will do a great job. Just waiting to see. The next barrel will be a 32" straight 284 set up to shoot the 180 bergers.

 

[mysticplayer]

Glad that you will have a replacement soon cause the barrel is kapoot.

Good luck with your new rig. Keep good notes and really be aware of shots that just don't make any sense.

As I got into precision shooting, I used to blame bad shots on a whole range of stuff and I chased down every possible solution. Ultimately, it came back that the barrel was the root cause more often then not.

I have been blessed to have owned a couple of "hummers". But I have also owned ones that were accurate but quirky.

The most common problem is a change in POI as the barrel heated up. And of course, as it fouled.

With good notes, I was able to narrow down the possible problem areas, really help to improve my overall shooting too. At some point you go, it's not me or set up - has to be the barrel.

As long as the problem repeats in a predictable manner, it is aggravating but workable. If not, time for a new pipe.

Maybe the reason you have a slightly used rifle is that the previous owner came to the same conclusion but gave up on it????

Jerry

Jerry

 

[C. Collins]

I have had many thoughts and that was one of them. One of my thoughts is the rifle got about 600-800 rounds down it and the previous owner did not want to go through a rebarrel and sold it while it still shot good. Everything is there, trigger, stock, pillar bedding, good scope, trued action, a new tube should really do the job.

Any experience with obermayers?

 

[XTR]

For me shooting F class the issue is barrel mirage contributing to poor visibility. I find that if it is not blowing hard enough to blow the heat away from the scopes field of view it just looks like you are trying to shoot through a dirty aquarium. My scope is focused at 1000 so I really don't see the mirage, just the soupy blur. I try really hard to never shoot without one.

 

[Bart B.]

I tried mirage bands on match rifles using both metallic and scope sights. With a scope and gusty winds across the firing point, that mirage band acted like a sail on a boat; moved it around enough to see the reticule move sideways across the target. With the rifle on a solid rest atop a bench, the mirage seen through the scope was negligable in mild winds and invisible in strong winds. I quit using them.

In bullseye matches shooting for score, I don't think one's needed. For group shooting, they may help in gentle cross winds, but anything above 5 MPH probably won't be seen.

Borrowed a 20X scope with a foot-long sunshade on it to shoot one day in the wind. That extra "sail" atop the rifle acted just like a mirage band; took it off and the holding area on paper was smaller.

 

[LHSmith]

With the rifle on a solid rest atop a bench, the mirage seen through the scope was negligable in mild winds and invisible in strong winds. I quit using them.

In bullseye matches shooting for score, I don't think one's needed. For group shooting, they may help in gentle cross winds, but anything above 5 MPH probably won't be seen.

I wish more competitors would quit using them.
Guy's -those silly looking Rube Goldberg things don't do anything but make pretty rifles ugly. :

 

[swampshooter]

Several years ago a few of the bench shooters decided to plastic wrap a section of the firing line so they could shoot and test barrels in the winter. They cut a window to shoot through and installed a heater to stay warm. It didn't work with the heat pouring out the window left them unable to see the targets. Lol. Seemed like a good idea.

[quote author=lmmike
Back in the Midwest, where I grew up we built a garage with a side room with 2 benches inside where we could poke our barrels out the window, at a private range. Also a higher window where we could shoot standing. In the beginning we shot out of an old barn with a pot bellied wood stove. When it got real cold we had the same problem on occasion with the mirage from the heat escaping out the window at both locations. but having A/C or heat as needed, year round was a real luxury that I miss. The property owner is deceased and the range is closed. It was nice for 30 years or so though. We also had benches and/or shooting areas outside that could be used when desired. Then you could shoot and run inside to warm up, or cool off. I surely miss that place along with our host who let his friends and neighbors shoot for free. What a geat guy.