Mirage - effect of distance?

[Joe Mamma]

I have a general understanding of mirage and some of the factors which affect it. However, one question I have is does distance (from the gun/optic to the target) affect the amount of mirage?

There are a lot of experienced long range shooters who recommend against high magnification scopes (let's say against higher than about 20x) because the effects of mirage limits their use and effectiveness.

However, there are a lot of experienced bench rest shooters who routinely shoot with 24x, 36x, 46x, and even higher magnifications. They would consider 20x magnification to be too low for their use, and recommend against them.

I am wondering why there is this distinct difference in opinion on this. Maybe it's because the bench rest shooters generally don't shoot as far as the long range rifle shooters? I don't know, but I would appreciate any thoughts on this.

Thank you.

Joe Mamma

 

[supercorndogs]

The farther away you are looking, the more mirage you are looking through.

 

[tna9001]

Hello Joe,

The needs of a practical rifleman (which is who I think you are referring to when you say long range rifle shooters?) and a bench-rest shooter are very different with regards to the type of scope they need.

High magnification is great as long as you are shooting from a stable position, there is plenty of light and there isn't much surface heating going on (mirage). If you're doing practical shooting you are probably better off at relatively lower magnification. Lower magnification gives less apparent retical movement, more light transmission and a wider field of view, also mirage, if present will be less noticeable. Now, add in shooting from unsupported positions and lower magnification is a necessity.

 

[Supersubes]

What they said^


With the exception of f-class, most target shooters aren’t shooting a few inches off the ground. They typically dial most all their elevation and windage and then use very minor hold corrections, where a tactical guy might take a long range shot with nothing but a hold. That won’t work with a very high mag scope and it’s narrow field of view. The tactical game may also involve scanning for targets, low light or shaded targets, and spotting ones own hits. All things not required of the paper punchers. Certainly the wide zoom ratios, among other features of modern scopes, means you can have a pretty good do-all scope, but you’ll have to decide what’s important to you. I prefer modest magnification scopes personally.

 

[rsb]

A couple of ads from my limited experience.
1. One can always dial down magnification if you need a wider field of view, are hunting less than 300 yards as many hunters do, need less reticle bounce you get from high magnification from an supported position, or have mirage.
2. There are two types or mirage. One from you scope looking over a hot barrel and normal heat generated downrange mirage. There are techniques to work around both.

 

[Gray Squirrel]

Mirage can definitely be disorienting (dialing back magnification can help with the distortion), but it can also help in calling wind at further distances. If you really study the mirage, it reacts to the wind similarly to the way tall grass or helium balloons on a string would react to the wind.