Wheels on the side of scopes ? ? ?

[Salop Matt]

Okay folks a bit embarassing asking this as iv been shooting a while and dont know what purpose these wheels serve that seem to be on more and more scopes. You know the big things that sick out of the side of a scope and look like they have been stollen from a wheelbarrow or small childs bike.

 

Can someone tell me what they are and what they do and there experience of them !

 

[Ozzy Fudd]

eh... im kinda in the same boat, never used them before, but i think (and could be drastically wrong here so dont count on it) theyre for focusing the scope...

[Mungler]

All together.... "the wheels on the side of scopes go round and round, round and round, round and round, the wheels on the side of scopes go round and round, all day long".

 

Normally the large wheel is for adjustment so you can "click in" your shot depending on the range.

 

They are a bit gimmicky and normally for (tactical) airgun users.

 

If you have a center fire rifle the bullet will probably fly flat for 150 yards and then only drop an inch or two (no need for clicking, just good old fashioned hold over).

 

Just don't ask about parallax adjustment.

[Jim145]

Mainly for use in FT with airguns. It allows you to rangefind the target and then zero the scope prior to your shot.

[Salop Matt]

So would never really be of much use on a .22 used to 60yrds or 17HMR out to 120yrds ?

[Vegeta]

Just don't ask about parallax adjustment.

 

Mung I thought those wheels were for parallax adjustment on side focus scopes and not elevation adjustments (have been wrong just once or twice though )

[MC]

Well whatever they are for, I defy anyone to understand that wikipedia link that Mung posted

[Baldrick]

The simple explanation of parallax is that it's the perceived movement of the target relative to the reticule, when the user's eye changes position. Adjusting the parallax reduces this relative movement. At least that's my take on it. I know that using parallax adjustment to focus a scope is incorrect.

 

Big side wheels are for Walting airgunners. The type of people who buy all the 'tactical' rubbish as advertised in Gun Mart.

[Ozzy Fudd]

spent an hour trying to work out that wiki post, then was all chuffed with myself because i found this simple explanaion in it...

 

If an optical instrument — e.g., a telescope, microscope, or theodolite — is imprecisely focused, its cross-hairs will appear to move with respect to the object focused on if one moves one's head horizontally in front of the eyepiece. This is why it is important, especially when performing measurements, to focus carefully in order to eliminate the parallax, and to check by moving one's head

 

unfortunately baldrick just posted this

 

anyway, simple way to eliminate this problem is to keep you cheek on the same position on the stock everytime

[Billy.]

Parallax adjustment.

[Flashman]

But Edward Fox tinkered with the big wheel in the Day of the Jackal and look what happened to that water melon: it must work, I saw it in a film...

[deershooter]

For those that dont know the big wheel on the side of the scope is the same parralax as the front eye piece type, however you dont have to have arms like an ape to reach it .

 

In air gunning they use it for range finding not clicking try and fit a high mag scope to a long action ie .2506 and see if you can alter the front eye piece with the stock in the shoulder its impossable

 

Deershooter

[Salop Matt]

Cheers guy I think i get the rough jist of it now !

 

And from that I guess it wouldnt be a nessesity on a rimfire such as 17HMR or .22 !

[deershooter]

I have one on my .17HMR as you can rangefind by looking at the side wheel when every thing is in focus

 

Deershooter

[Dave-G]

I think the large wheel is bolted onto/over the existing smaller parallax wheel to facilitate additional numbers that relate to what range the scope is "in focus" at - therefore the air gun user in competitions know how much hold under/over to apply. The larger wheel also moves the relevant markings closer to his eyes while in the aim position so it's esier to read the range.

[Harnser]

Iam still confused .Mungler you shouldnt have posted that link i will be burning the midnight oil tonight trying to understand it all . I really carnt remember missing a deer with the technique and kit that i use at the minute . Is understanding this paralex thing going to make me a better shot . Or will it be one of these always ajusting something just in case . A very confused Harnser .

[chrispti]

I think the large wheel is bolted onto/over the existing smaller parallax wheel to facilitate additional numbers that relate to what range the scope is "in focus" at - therefore the air gun user in competitions know how much hold under/over to apply. The larger wheel also moves the relevant markings closer to his eyes while in the aim position so it's esier to read the range.

 

 

Its just that, used for focusing and range finding, you place targets out at various ranges, ie; 10 20 30 40 50 yrds etc etc. You then focus in on each target until you have the best/ clearest pic and mark or write the distance on the side wheel. Then when you are out in the field all you need to do is focus in on the target and read off the distance from the side wheel and there is you range, apply the pre established mill dot or aim point etc and wala.

 

OR, just purchase a lazer range finder

[Dunkield]

Used for FT Airgun shooting, they are focus wheels not parralax adjusters, and they are used for range finding.

According to this laser range finders are not allowed:

 

Unlike rifles, your choice of suitable scopes is very limited and can be expensive. In FT, competitors are permitted to range find targets using high magnification scopes, but not dedicated lasers. Once you know how far away the target is you can adjust your aim point to compensate. To do this accurately the scope must have a magnification of at least 32X, but a higher magnification will generally improve range finding. Most general purpose scopes only go to about 12X or 16X magnification. Many of these claim to range, but they don't, or at least not to the level of accuracy required for FT. Another problem is the ranges we are interested in are relatively short, out to a maximum of 55yards and a requirement to focus at 8. Many of the better scopes on the market are designed for live round rifles which probably wouldn't be used any closer than 55yards! As a result the closest range at which they will focus is about 50 yards, and often 100, totally useless for FT. This gives a relatively limited number of choices, but a good scope will stay with you for a long time. An option is to get a scope modified to be suitable for FT, but this can be an expensive route.

 

Another source is the 2nd hand market, but good scopes tend to be held onto and it may take a while to find the right one. It's tempting to try and get away with a low power scope, but it's just not worth it. If money is tight, spend less on the rifle. A really good scope will help you achieve good scores on even an average gun. A low magnification scope will always give poor scores regardless of the rifle. We've seen or used just about every scope on the market at some point, and regardless of what you may hear, a scope with less than 32X magnification will end up being replaced very soon after buying it. Although in FT the maximum target is only 10 yards further than in HFT, the relatively low power of the rifles means the pellet drops an additional 63mm at 55 yards compared with 45 yards, enough to completely miss the kill zone, so ranging is more critical in FT than HFT.

 

There are 2 main types of range finding scopes, those that have a sidewheel and those that have the parallax adjustment on the front of the scope. Both work, but sidewheels are usually easier to operate and read the distance without breaking your shooting position. The other advantage of a sidewheel is the ability to fit an over size wheel that will give greater spaces between the ranges by virtue of it's increased circumference.

 

Another aspect of scopes are the physical dimensions which can sometimes be misleading. The objective lens diameter (the one at the front) determines how much light the lens collects and therefore how bright the sight picture is. A big lens will gather more light that a smaller one of the same quality. This can be really important on an overcast day or if shooting at dusk or dawn. The important thing to realise is that not all lenses are equal. Companies such as Leupold and Bushnell spend enormous amounts of money on developing special glass and coatings to maximise image clarity, resolution and brightness and as a result their 40mm objectives outperform most 50mm lenses on brightness and clarity by some margin. With top quality optics you can see incredible detail at long distance which may just be a blur on many others that have much larger objectives. So big is not always better. The scope tube is also generally available in 2 sizes, 25mm and 30mm with the 30mm tube usually touted as better. Again, high end scopes often have 25mm tubes but the quality of the internal mechanisms and lenses still mean they outperform 30mm tubes, so again don't always believe that bigger is better. Of course Leupold and Bushnell scopes are towards the top end of the price range and are more expensive than the typical air rifle scope, but don't be drawn into the bigger is better debate, quality usually has far more bearing on the matter.

 

An often asked question at the club is 'what's the best FT scope I can get for under £150?', and the answer is usually 'none'. This is the one part of the sport where parting with cash is the only option. There are many really good £150 scopes around but none rangefind at the critical distances we need. You could use a £50 scope, but it will cause you to miss targets. If you're serious about competing this is the one area you can't scrimp although you could compete in the 'sporting class' with almost any scope.

[chrispti]

I was refering to them for its use in the field not FT,

[Vegeta]

Used for FT Airgun shooting, they are focus wheels not parralax adjusters, and they are used for range finding.

According to this laser range finders are not allowed:

 

I was under the impression that the side focus and adjustable objective did the same thing. Focus on the target which removes parallax error. I think this must be true otherwise why do top end target scopes (Nightforce, Leupold etc) not have both

 

Side focus and AO (Adjustable Objective) scopes allow you to focus on the target, this removes parallax error afaik