When we buy a scope, there are a variety of brands and models to choose from.
To begin, it is clear that there are two major groups of view, increases the fixed and variable.
The sights fixed increases were the first to appear. The biggest advantage is its simplicity. Have fewer parts, fewer movements therefore have less defects and breakdowns (According distributors, given equal amount, are less prone to 3 times drawbacks variables), the eye distance is constant, the reticle always has the same apparent size and tend to have a wider field of view than a variable of the same diameter and the same goal and increase quality of components tend to be cheaper. The drawback: they are fixed magnification, so you make a choice to increase and then live with it.
The variable magnification view of birth in order to use a weapon / look in various shooting disciplines, for example by selecting a 4x increase to mount hunting or making long shots in selecting 12x mountain. Due to the greater number of its component parts, and more sophisticated, they need, the same quality of materials, a more careful preparation and more control than fixed magnification view of which is reflected in the price, also for the most part or usually heavier than fixed or fragile. A relevant point of view only increase case variable is the location of the reticle in the optical system:
Location of the reticle in the first focal plane.
Used widely by European firms, it is located in front of the system that changes the magnification of the scope, so the grid increases / decreases in size (as the other objects in the field of view) to increase / decrease the apparent size increases changing the same (but not actual), the advantage of this system is that the impact point remains unchanged when changing magnification, and always maintains the same ratio with the blank size, allowing x instance estimator grids with the use This at any magnification, the downside is that in very broad view of the grid increases may seem imperceptible to very low magnification or too thick at maximum magnification.
Location of the reticle in the second focal plane.
It is the most used in USA and East and is defined as when the reticle is located behind the system that changes the magnification of the scope, ie, in the second focal plane. So to increase or decrease the grid increases apparent size does not change (although actual size) and this may be an advantage when using a large number of variable increases or for precision shooting (at magnification up the cross and can not grow an aim finer), the major disadvantage of this location is that any tolerances in the lateral or longitudinal centering of the lens system relative to the reticle will generate an impact point change when changing the magnification (x ex. a tolerance of 0.25mm generates a change in point of impact of 3 cm. to 100metres), needless to say that economic models are not noted for their strict quality control and tolerances, changes therefore have considerable impact point. Even brands that care toughness of materials to prevent wear, control and adjust the size of the pieces can not entirely eliminate the problem as due to thermal expansion, to use a viewer in any climate, certain clearances should be allowed . Therefore the aim of increasing economic price variable (even more if offer reticulum in the background and lots of aggregates as parallax correction, illuminated reticles, etc..) Should not be considered reliable if we look a sight. The choice of a variable should be on highly recognized brands in the field of optics that do not want to risk his reputation.
The theme of the sights with variable magnification introduces us to the question of how much increases are what we need to practice the discipline, a variable scope can be very versatile but a poor choice of necessary increases can cost dearly. Many newbies to go hunting merely place the wheel on a high magnification, as if they were to hit more. We are not in a polygon with a fixed target in broad daylight. Result greater increases reduce the field of vision, tremors pulse increase, decrease the exit pupil and light making it impossible to shoot at a target or moving very close.
To evaluate that increase is needed is necessary to take into account:
First define the type of weapon it will be fitted is a compact rifle, a bolt action rifle with long barrel or maybe a dangerous weapon for hunting. Suppose the choice of weapon is done correctly according to the discipline practiced. The compact weapons like Palanqueros moderate scope, Ruger Mini, SKS, etc. cavalry carbines. They carry a compact look with eye distance 6/7cm to face well with short heads. The objective lens should be of moderate size to be mounted very low and encourage instinctive shooting, much increase means also a narrow field of view that makes the shot moving in the woods or mountains. I lean a fixed magnification sights, including 2.5x and 4x or variable from 1.5 to 4x. Not having much increase will not need a large lens to be light, if the quality of the device is recognized can be illuminated reticle.
Dangerous weapons for hunting, must carry a sight to resist violent undoubtedly a setback, here only the highest quality variables are suitable, the increases should be between 1.5 and 4x maximum lens diameter and no more than 32mm. For these powerful weapons, the eye distance is critical, it must be of 8cm or more (also indicated the scout view, which are mounted ahead of the action on the barrel).
In the arms 22 lr recreational shooting a sight fixed 4x is the ideal choice if you are going to use for competition shooting or alimañero largest increase will be necessary and proper approach looks at short distances (specific models rimfire / airgun) most rifle sights to focus incorrectly within 50m producing parallax errors, instead of compressed air and parallax corrected 22 from 7 meters. In terms of quality, often not looking to invest in these weapons x which is only 22, I disagree with this attitude, many brand-name 22 50/75m grouping better than a large caliber rifle.
The inherent accuracy of the gun and of little worth putting on a scope for a gun rest bench that brings in 10 cm, at 100m. The type of terrain and distance shooting, either plain, mountain, hill or mountain closed. For short to average 2.5x, 3x, 4x fixed within 1-4x, 1.5-6x, 2-7 in the variables. The choice for middle distance / long are the variables of 2-7x, 3-9x, 2.5-10x etc. and fixed between 6x and 8x.
For very long shots of plain, is perhaps the most versatile 10x (preferred by military snipers). Since the shots will be the long range field of view will be even wider. For highly accurate shots over long distances, such as shooting or bench rest alimañero, yes would apply a scope of over 10x, the most widely used in fixed 16x is 24x followed, there are many options in variables: 6 6-24x-18x, 8-32x etc.
Please note that when climbing increases the parallax effect is considerable, and on hot days the thermal reverb is more evident at high magnifications, negating the possible advantage.
A separate issue within the long distance view of the grids is the Mil Dot.
First, in order to increase the variable, if the reticle does not change size when switching increases (first focal plane). In view with second focal plane reticle, the reticle is useful only to a specific increase. It is also important to know that over the years have appeared mildot reticle view with Southeast Asia made cheaply, the combination is the worst, because this lattice requires maximum precision and uniformity in the construction, and these models just can not offer guarantees to respect (plus the fact that in these devices the value of clicks is often fickle).
Some points clearly differentiating a tactical look firing the robustness in construction, the value of the clicks (tactic has a sight moa clicks ¼, ½ or directly moa drop compensator projectile, while a shooting has clicks of 1/8 MOA) and the adjustment range of the grid (a tactical look has an adjustment range of over 80 moa, the shooting less than half of that value). Lighting conditions. If you are hunting in poor light conditions the goal should be at least 42mm, 30mm tube, increases should be below the 8x and choose the crepuscular light transmission rate should be included in the specification. A large objective lens does not imply in itself good light, is critical lens quality, the treatment applied to it, the light transmission and a design that not waste light reflexes causing parasites or aberrations.
As a rule Gral The diameter must be such to generate an exit pupil of 5.5 to 7 mm on the most commonly selected magnification (lens pupil = diameter / number of x).
Remember that the biggest advantages of a telescopic view are put on the same plane and white grid and increase the brightness, not both increases, so increases in one variable should be kept as low as possible, be better to invest the money in optical quality that excessive increases.
The quality of look should be consistent with other elements of the team, both the shooter, the gun assembly and look are a set and the results will be the average quality of all conjugates.
As important as the size of the target increases, etc.. It is the choice of the grid. This should fit perfectly to the discipline to practice shooting or hunting, may be stated two general characteristics:
1) That the minimum possible obstruct vision.
2) Make a design that does not distract our attention and favors rapid target acquisition. As reticles illuminated.
It is important not generate reflections in the looking and the brightness is moderate, which could reduce the diameter of our pupil.
Most common designs: