What you should know about sights

What is the task of a sight set?

The sight set is the connection of the target and the shooter's eye. With the development of precise sight sets it has become possible to judge the accuracy of a gun. With regard to today's high technological standard of guns with perfect shooting performance, tailor-made stocks and high-tech trigger systems the sight set thus plays a very important role.

Why do you need an aperture sight set?

The front and rear apertures make use of the capacity of the human eye to center round objects to each other. This type of sight set is the most precise one of the open sights for rifles and has almost replaced the sight set of peep sight and post in long rifle shooting .

Why is it necessary that sight disc aperture and front sight insert can be adjusted?
The main field of use of adjustable sight sets are changing light conditions at the shooting ranges and the various sizes of targets of the different shooting disciplines. It must be possible during competitions as well as training to reach an optimum adjustment of the sights very quickly – this is one of the most important steps to success. The shooters save a lot of time and tension with the adjustable font and rear apertures which can be adjusted very easily without any tools with the help of graduations.

Iris discs are round – why? Because the pupil of the eye is round. The pupil also works like an aperture: it becomes smaller when it is bright and it becomes larger when it is dark to get as much light as possible. Leonardo da Vinci already observed the optical effects of a simple hole. He also recognized the connection of the diameter of the hole and the focus. At the beginnings of photography experiments were made in which there was just a hole in the front wall instead of a lens. An iris disc with a ring insert works on the same principle. The correct adjustment of the two diameters results in an optimum focus – the eye is "forced" to see accurately. The proper adjustment of the rear iris is to first open it and then slowly close it untill the light dims slightly. Usually that will be less than 1.0 m unless the range is very dark. That setting will give the shooter the greatest depth of field available for that amount of light and also provide the best condition for good sight alignment.

Does the width of the aperture change when the iris system is adjusted?
No! In ahg-Anschütz products the iris system is situated between two glass discs or a thin metal frame. The width of the aperture thus remains unchanged when the diameter is adjusted because the inner and outer diameter change proportionally. The latest ahg iris disc has a patented design which will replace the common iris inserts. Up to now inserts which consist of three individual parts are used – mounting needs a lot of time and is complicated. The new iris consists of only one part. It is therefore easy to mount and robust in use.

Which manufacturing processes and materials are used?
In contrast to most cheap products where injected plastic parts are used the ahg sight sets consist of a variety of different materials, which – according to their properties – are used at that place of the sight set at which the characteristics of this material entail specific advantages. One example is aluminum which - due to its low weight and high color fidelity and durability after an anodizing process - is used for the robust body of the sight sets. An other material is brass which - due to is heat treated special alloy - is responsible for utmost adjusting accuracy and consistency of the sights. A further material is precisely ground glass which in contrast to molded glass guarantees a target with a minimum of scattered light and reflection and a maximum of antiglare properties and depth of field.

How important is the consistency of adjustments?
Shooters very often practice at several indoor ranges with different light conditions. Once the shooter has found the correct adjustment for a special shooting range he should be able to quickly repeat this exact adjustment. The shooters wants to concentrate on aiming and shooting instead of loosing a lot of time for getting used to the new circumstances.

Which kind of front sight inserts are there?
You basically have clear front sight inserts and inserts with a lateral or cross hair. While actual aiming is done through the aperture the lateral or cross hair can be used as a means of orientation in order to avoid canting. With the ahg Vario sight set the shooter has the possibility to adjust the lateral hair to a cross hair by simply turning the ring. The adjustment of the sight does not change. It is also important to know that the adjustment of the lateral or cross hair can be adapted to the individual canting of every shooter without having to use any tools. This is a feature of the Vario-Swing.

Which role does time play in the aiming process?
A fast and clear focus of the target is important as the shooter only has a short time available in which optimum concentration is possible. If the shooter needs too much time for aiming this will result in a loss of concentration and condition and thus in a worse result in the individual shooting process and in the competition as a whole.

Do polarization filters polarize?
The shooter can reduce reflections with a polarization filter. This can be seen very well when the polarization filter is directed at the reflecting surface of water. When you move the adjusting rings back and forth you can fade the reflections in and out. Ahg sight sets make it possible to adjust the grade of polarization separately from the grade of darkness which results in a high-contrast target. The iris sight with polarization filter combines these advantages. Both polarization discs can be moved out of the beam path. Thus free vision is possible if necessary.

What do shooters need color filters for?
Additional color filters can be used in sight sets to protect the eye from tiring white light influences. Various colors are recommended for different light conditions: Yellow filters for example can be used for hazy vision – they make the target clearer. In many cases the "correct" colors are subdued to individual preferences or eye reactions. So just try which color is good for you for the various light conditions.

Large range of adjustment – why?
While most sight sets only cover the adjusting range for standard adjustments the ahg sight sets offer a larger range of adjustment – also for extraordinary situations. The adjusting range of the aperture inserts was increased by 25 % from 2.0 mm to 2.5 mm.

Large or small adjusting range?
The choice of aperture insert diameters is a very individual matter. Illumination, the color of the target , the state of the day and always changing powers of vision play an important role. If you feel unsure you will choose a larger diameter. If you feel good, and if there are good light conditions you will prefer a smaller diameter. Top shooters get better or worse results if the diameter changes only by 0.1 mm. Good sight sets have no play, are variably adjustable and have fine adjustment properties.


fig. 1: A perfect group – the goal of every shooter. This is a 10.9. The space around the mirror shows that the shooter selected a large aperture.	fig. 2: In this example the shooter also would touch the "10". The larger adjusting range offers more freedom of movement.	fig. 3: A narrow adjusting range like this needs a certain perfection. In spite of the smaller aperture adjustment this group would have the same result as in fig. 2.

What is a Duo iris aperture?

What is a Duo iris aperture?
The aperture width can be extremely narrow and extremely wide. The Duo iris aperture is available as a clear aperture which is situated between two glass discs and as a cross hair aperture. The Duo iris aperture offers the possibility to switch from lateral hair to cross hair. In addition it has a variable adjustment of the canting angle. Two ranges of diameter are available. The Duo iris aperture can thus be used for all disciplines.

Do the hairs support the aiming process?
Some shooters use the hairs in the aperture as a means of orientation to control canting. There are also models in which the cross hair can be switched in and out because it was or is not allowed for all disciplines.
Other shooters, however, are confused by a lateral or cross hair. They prefer the free space in the aperture. Depending on the discipline they use a spirit level or a canting support that can be mounted to control canting.

Which sight disc apertures are there?
Apart from the simple iris sight disc in which only the size of vision can be adjusted the ahg models with their integrated color filters and separately working darkening and polarization filters really offer a large choice. According to the referring national regulations the iris sight disc apertures are supplied with an integrated diopter regulation of +/- 3.5 for older shooters. The length of this optical component is extraordinarily short. Helmut Brunner senior has developed a lift gear whose technology has been unknown in gear construction up to now and which is patented.

For which target rifles are there ahg sight sets?
While the aperture inserts for the threads fit to all common target rifles, the sight disc apertures are delivered with the necessary adapters. In case of special requirements the ahg competition service will help.
The range of products of ahg consists of aperture inserts, sight disc apertures as well as accessories for all rifle disciplines from air rifle to 300 m and long range shooting.

Reflection
Whenever beams of light meet another material, for example when they meet glass from the air or vice versa beams are reflected. Beams of light which are reflected do not get back to the eye which impairs vision. It is therefore very important that the corresponding surfaces are reduced in their reflecting capacities. The ahg color filters are constructed in such a way that as little light as possible is reflected. What is important is the correct arrangement. In the ahg articles the glass is situated in front of the iris: glass – iris – eye.

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