Comparison Hawke Vantage 3-9x40 30/30 Duplex vs Gamo 3-9X40 AO

The offset is the distance between the eyepiece lens and the exit pupil of an optical instrument (see "Exit Pupil Diameter"). Optimum image quality is achieved when the exit pupil is projected directly into the observer's eye; so from a practical point of view, offset is the distance from the eye to the eyepiece lens that provides the best visibility and does not darken the edges (vignetting). A large offset is especially important if the sight is planned to be used simultaneously with glasses — after all, in such cases it is not possible to bring the eyepiece close to the eye, and it must be at some distance from the glasses so as not to hit the glass due to recoil.

The diameter of the area visible through the sight from a distance of 100 m — in other words, the largest distance between two points at which they can be seen simultaneously from this distance. It is also called "linear field of view". This indicator is more convenient for many users than the angular field of view (the angle between the lines connecting the lens and the extreme points of the visible image) — it very clearly describes the capabilities of the device.

In sights with magnification adjustment (see above), both the entire range of width — from maximum to minimum — or only one value of this parameter can be indicated. In the latter case, the largest width of the field of view is usually taken, at the minimum magnification.

A complex indicator that describes the quality of any optical system (including sights) at dusk — when the lighting is weaker than during the day, but not yet as dim as in the deep evening or at night. It is primarily about the ability to see small details through the device.

The need to use this parameter is due to the fact that twilight is a special condition. In daylight, the visibility of small details is determined primarily by the magnification of the optics, and in night light, by the diameter of the lens (see above); at dusk, both of these indicators affect the quality. This feature takes into account the twilight factor. Its specific value is calculated as the square root of the product of the multiplicity and the diameter of the lens. For example, for an 8x40 scope, the twilight factor would be the root of 8x40=320, which is approximately 17.8. Models with adjustable magnification (see above) usually indicate the minimum twilight factor corresponding to the minimum magnification.

The lowest value of this parameter for normal visibility at dusk is considered to be 17. At the same time, it is worth noting that the twilight factor does not take into account the actual light transmission of the system — and it strongly depends on the quality of the lenses, the use of antireflection coatings (see below), etc. Therefore, the actual image quality at dusk for two models with the same twilight factor may differ markedly.

The possibility of manual adjustment of the sight from parallax, by the user himself. For this purpose, the design provides a corresponding regulator.

Parallax in this case is a phenomenon when, when the eye deviates from the optical axis of the sight (from the center of the eyepiece), the aiming mark visible to the shooter also shifts, while the sight itself remains motionless. As a result, if the eye is not exactly in the center, the visible position of the mark does not coincide with the actual aiming point. This phenomenon is especially pronounced in optical sights (see "Type"), and many collimators are also subject to it, although not to the same extent (but "night vision" and thermal imagers are free of this drawback, since the mark is displayed on the built-in display).

To eliminate this phenomenon, a specific adjustment is used - parallax adjustment. It is usually done right at the factory. However, the sight can be adjusted from parallax only for a certain distance, and with significant deviations from this distance (more than 30% downwards or 60% upwards), this effect begins to manifest itself again. It can be compensated for by an ideal insert ("eye strictly in the center"), but even for experienced shooters this can be difficult, especially when shooting standing, offhand and in other uncomfortable positions. In light of this, some models also provide manual parallax adjustment - a regulator that allows you...to set the adjustment distance at the user's discretion. In addition to the situations described above, this function will be especially useful for novice users, as well as for high-precision shooting at long distances.

Optical sights with parallax adjustment> can be equipped with a wide ring on the AO (Adjustable Objective) lens or a drum on the SF (Side Focusing) control unit, on which additional accessories for fine-tuning the focus in the form of wheels are installed.

A type of coating used in scope lenses. Anyway, we are talking about the so-called antireflection coating, which is the thinnest film (single or multilayer) on the surface of the lens in contact with air. The properties of this film are chosen in such a way as to minimize the reflection of light from the glass surface. The meaning of this function is not so much to reduce the brightness of glare that can unmask the shooter, but to increase the light transmission of the optics and, accordingly, the quality of the image visible through it.

Modern sights can be equipped with the following types of coatings:

— Illuminating. In this case, the simplest option is implied — an incomplete single-layer coating. The term "incomplete" means that not all lens surfaces are coated (although there may be several coated surfaces). Such enlightenment is inexpensive, however, the image quality is relatively low — in particular, because a single-layer film is most effective only for a part of the visible colour spectrum.

— Full illumination. Fully coated means that all surfaces of the lenses that come into contact with air have a special coating; in this case it is single layer. Such a coating is more expensive than a simple anti-reflective coating, but the quality of the “picture” when using it is higher, because. light distortion at the transitions between glass and air is minimized.

— Multi-layered illuminating. Incomplete AR coating (see above)...using multilayer films. Thanks to multiple layers, the anti-reflective coating covers the entire visible spectrum, which allows you to achieve a brighter image with less colour distortion compared to single-layer coatings; However the price of such devices is higher.

— Full multilayer enlightenment. The most advanced option: multilayer coating on all lens surfaces used in the design of the sight. Features of full and multi-layer coating are described separately above. Here we note that their combination is typical for high-class sights, because. it provides the highest quality image, but it is not cheap.

The type of aiming mark (reticle) provided in the device. There are models for which several options are indicated at once: this implies the possibility of switching between them.

As for specific varieties, in collimators, all brands have a common specificity - they should provide the convenience of quick aiming at relatively short distances. But the reticles of optical and other similar sights can be divided into hunting and tactical (sniper) sights. The former are relatively simple and have a minimum of additional elements, as they are designed for short distances and relatively large targets; and the latter are designed for high-precision shooting, military and police use, and therefore must be supplemented with various elements for measuring angles and taking corrections on the go, including between shots.

Among the specific types of grids most popular in our time are the cross with divisions, BDC, duplex, cross, half-cross, cross with a dot, cross with a circle, herringbone, rangefinder, dot, circle with a dot and circle with 2 points. Here are th...e main features of each:

— Cross with divisions. One of the most popular types of "tactical" reticles used in optical sights. The key element is the crosshair, on the lines of which additional dots are applied. The distance between the points corresponds to a strictly defined angular size; initially it was 1 MRAD (1 "mil", hence the name), however, in modern sights, other values \u200b\u200bcan be found, they should be specified according to the instructions. In addition, such grids can differ in the number of points, the presence of thickening on the lines (as in the duplexes described below), etc. Be that as it may, such a grid is very convenient for estimating distances and making corrections on the fly, many professional shooters consider it almost ideal for high-precision shooting, including at long distances, besides, the original cross with divisions (Mil-Dot) is widely used by military and police snipers around the world.
We also note that there is also a collimator variety of "mildots" - in this case, the grid looks like a circle with a dot in the middle and several dots below it, with an interval of the same 1 MRAD. However, when using collimators, the real need for making vertical corrections rarely arises, and this option is not widely used.

- Duplex. Reticles for optical and night sights (see "Type"), which look like a classic crosshair with different line thicknesses: they are thin in the center, and noticeably thicker near the edges. The meaning of this combination is that thin lines do not “clutter up” the field of view at the aiming point, and thick lines remain visible even under adverse conditions (for example, at dusk) and allow you to aim at least approximately. In addition, the thickness of large lines and the distance between their edges can correspond to well-defined angles, which allows some of these sights to be used even as simple goniometers. However, these possibilities are very limited, and in general, "duplexes" are classic hunting nets.

- Half cross. Hunting net, the main elements of which are T-shaped. One of the varieties of semi-crosses - "German grid", it is also "stump" - consists of a vertical line from the edge to the center of the sight and two horizontal lines that do not reach it; the aiming point corresponds to the upper point of the central "stump", and the thickness of the lines and the distance between them can be specified in the documentation - this allows you to carry out the simplest measurements of angles. A more modern version of the half-cross is the crosshair, in which one line (from the center to the top edge) is much thinner than the rest, or even absent altogether.

- Dot. In its pure form, the dot is used exclusively in collimator sights (see "Type"). This is an extremely convenient option for such devices: there are no unnecessary details in the field of view of the shooter, only a mark that clearly shows exactly where the weapon is aimed - more is often not required when using collimators. The disadvantages of the dot in comparison with other marks in the sights of this type include less visibility, especially in bright ambient light. However, many sights allow you to set a fairly high brightness of the mark, and sometimes even increase its size, increasing visibility. Also note that for a point, the angular size can be specified, which can be useful for quick estimation of distances.
In addition, the dot can also be used in optical and night sights, but in such cases it is usually used as an addition to another scale - for example, it additionally highlights the intersection of lines in a semi-cross.

— Circle with a dot. Another type of marks, used in collimators as the main one, and in other types of sights - as an addition to a crosshair or other more traditional grid. However, the latter is rare, so let's focus on the first option. Compared to another popular "collimator" mark - a dot - the circle covers more visible space, however, it is very noticeable and often turns out to be more convenient when shooting offhand or sharply turning the weapon to the side. In addition, for both the circle and the dot, it often indicates the exact angular size, which gives extended (compared to the usual dot) possibilities for using the aiming mark as the simplest goniometric (rangefinding) scale.

- Circle with 2 dots. A variation of the circle with a point described on top, having a second, additional point - usually below the first, at a strictly defined angular distance from it. This expands the possibilities for using the sight as an impromptu rangefinder, and also allows you to "on the move" take an amendment when shooting at long distances - just aim at the second, lower point. However, such opportunities for collimators are extremely rarely required, so this option has not received much distribution either.

- Cross. Features of this type of brand depend on the type of sights in question - optical / night or collimator (see "Type"). In classical optics, a cross is the simplest crosshair of thin lines of the same thickness. Naturally, in terms of general specialization, such reticles are hunting, but they are also found in a fairly advanced variety of sights - sports models for benchrest (shooting from a machine gun at maximum range and accuracy). The convenience of the cross in such an application lies in the fact that the lines have a minimum thickness and practically do not block the view. In nightlights, this type of grid is usually one of several options available to choose from. But in collimators, the cross is in many ways similar to a circle with a dot - it is provided as one of the large, well-marked marks with a clearly defined angular size.

- Cross with a dot. A grid in the form of a crosshair of two lines (as a rule, quite thin), at the intersection of which a clearly visible point is applied. It is in this form, as a rule, that is used in collimator and other types of sights. In the first case, such a stamp is actually a slightly modified version of the usual cross (see on top). And in optics, the presence of a point allows you to additionally highlight the crosshairs, which is convenient in some situations; the general purpose of such sights is, of course, hunting.

- A cross with a circle. Stamp in the form of a cross, complemented by a circle. It can also be used in different types of sights and has its own specialization everywhere. In classical optics, such a grid usually has a hunting purpose, although there are also varieties with additional marks that expand the "tactical" functions. And even in the absence of such marks in the characteristics, the angular size of the circle is usually specified, which provides additional opportunities for impromptu measurement of distances. We also note that the cross itself can be both ordinary and duplex (see on top). The situation is similar in night sights, however, there a cross with a circle is usually only one of the available mark options. As for the collimators, they can use both a full-fledged crosshair in a circle, and a ring with “rays” protruding from it; in any case, such a mark is more noticeable than an ordinary cross.

— BDC. This reticle got its name from the English phrase Bullet Drop Compensation, which translates as “bullet drop compensation”. The BDC ballistic reticle allows for range correction based on the bullet's trajectory. It is calibrated for a specific ammunition and sharpened for quick aiming at various distances using the same type of bullets. Distance markers in a ballistic reticle are hash marks, circles, or dots. The main sign of their placement is that the vertical markings have different gaps, increasing towards the bottom. An additional distance scale is often placed in such grids on the "six" shoulder. In addition, the ammunition for which the reticle is calibrated is usually indicated (caliber, bullet weight, weight).

- Christmas tree. Informative reticle resembling a Christmas tree in its structure. Actually, this is where the name of this type of grid came from. Each array of dots on its "six o'clock" arm is longer than the previous one - the marks increase in width when viewed from top to bottom from the central crosshair. These markers are used to correct for wind drift, which is extremely important when conducting aimed fire at long distances. The most common herringbone reticle is found in hunting hybrids, tactical sights, and military rifle scopes.

- Rangefinder. This type includes all grids that do not belong to any of the types described on top and provide for special markings for measuring angles and distances. The specific design of such markings may be different, but the general principle of operation is the same everywhere: rangefinder marks allow you to determine the angular size of a visible object, and if the linear size of this object is known, you can easily estimate the distance to it (at least approximately). Each type of rangefinder reticle has its own rules for use.

Units of measurement that are used in the marking of goniometric elements of the reticle. In our time, there are two main units: - MOA. The abbreviation for minute of arc is 1/60 of a degree. Initially, this unit is associated with the English system of measures and is convenient primarily for calculations in yards and inches: at a distance of 100 yards, an angle of 1 MOA corresponds to a linear dimension of approximately 1 inch. In the more familiar metric system for us, this gives 2.91 cm at a distance of 100 m. We also note that this unit is a kind of accuracy standard: it is believed that a full-fledged sniper rifle should give a spread of no more than 1 MOA.

— MRAD. Conventional designation miradian - an angle of one thousandth of a radian (approximately 0.06 °). Also in the jargon of snipers, this unit is called "thousandth", or "mil". It is already tied to the metric system: at a distance of 100 m, an angle of 1 MRAD corresponds to a linear size of 10 cm (approximately 3.5 times greater than 1 MOA).

The choice for this indicator largely depends on the personal preferences of the shooter. We also note that inconsistencies are often found in low-cost sights: their drums are marked on the MOA scale, and the reticle is in MRAD units.

— Dust-, water protection. Protected housing that prevents dust and moisture from entering the delicate components of the sight. This feature is highly desirable if the sight is planned to be used in adverse conditions — for example, during a long hunting trip, where there is a chance of encountering bad weather. However it is worth considering that the specific degree of protection may be different, it should be clarified according to the documentation for the sight. However, almost all “protected” models are able to endure rain at least without problems.

— Impact protection. Special protection that prevents damage to the sight during impacts and shocks — for example, by accidental falling or contact with a foreign object. The effectiveness of this protection may vary for different models, but in most cases it at least allows you to transfer the fall onto a hard surface from a height of 1 – 1.5 m. with a high probability it will turn out to be useless — the impact force will be much greater than that for which the device was originally designed. In addition, after any strong impact, the sight will have to be re-aligned. However, additional protection anyway improves the overall strength and reliability of the device.

— Filling with gas. A feature that is found exclusively in sights with closed cases (see "Design"). Such cases are made airtight, and th...e internal space in them is filled with an inert gas — for example, nitrogen — with a minimum content of water vapor. Thanks to this, the optical elements of the sight do not fog up from the inside, and metal parts do not oxidize due to contact with moisture. In addition, such an air-tight housing, by definition, is also dust and moisture resistant (see above).

— Rangefinder. A device that allows you to measure distances to objects visible in the scope. Do not confuse this function with rangefinder markings and other similar reticles (see “Reticle type”): in this case we are talking about a separate device, usually in the form of a laser rangefinder. Such equipment greatly simplifies measurements: there is no need to bother with special calculations for the angular dimensions of visible objects, just one click of a button is enough, and the accuracy of laser devices is very high — on the order of several centimeters at distances of hundreds of metres. The main disadvantage of this feature is the high cost; in addition, additional equipment increases the weight and dimensions of the sight. Therefore, built-in rangefinders are found exclusively in professional models designed for high-precision shooting.

— Level. A device that allows you to control the deviation of the sight (and, accordingly, the weapon) from the horizontal position — namely, the tilt to the right / left. Such a need arises primarily with high-precision shooting: even a slight slope, imperceptible to a person, can give a significant deviation, especially at a great distance. Levels may have a different design and principle of operation, but they are always set so that the shooter can see such an indicator at the same time as aiming. For example, in optics (see "Type"), a bubble bulb is placed above the lens or to the side of it, while in "night lights" and thermal imagers, data from an electronic sensor is projected directly into the eyepiece.

— Lantern. A flashlight mounted directly into the body or on the body of the sight. A rather specific function that is rare: at distances where optics are mainly used, a searchlight is needed, for "night lights" an IR illuminator is relevant (see below), collimators are more convenient to use with a separate underbarrel or hand "tactical" flashlight. However, the built-in lamp cannot be called completely useless. So, in optical sights, it is usually combined with a laser designator (see below), allowing you to effectively use the laser in low light conditions. And in the case of a collimator, the LEDs built into the frame are more compact than a separate underbarrel flashlight (which, moreover, can not be installed on every weapon that is compatible with a collimator).

— Laser designator(LTC). Device for quick aiming at short distances. The idea of such a device is extremely simple: a laser beam shows where the weapon is aimed, creating a clearly visible mark at the point of impact. This allows you to shoot accurately, even without looking into the main sight — including "from the hip" and from other emergency positions, which is especially useful in situations requiring maximum reaction speed. LCC is relevant only at minimum distances, but this is not a drawback, but a feature that can turn out to be a definite advantage. For example, a "laser" can be a great addition to a telescopic sight, which by itself is useless at short distances.

— Compatibility with night vision devices. Possibility of using the sight with separate night vision devices. Most often, this feature is found in collimator sights (see "Type") — it means that the brightness and colour of the collimator mark make it possible to clearly see it even through night vision devices. But optical models with such compatibility are extremely rare: firstly, it is technically difficult to implement, and secondly, for sniper shooting in the dark, there are specialized night and thermal imaging sights that are more convenient and effective than a combination of night vision devices with classic optics.

The weapon class that this scope can be used with.

Different classes of weapons differ in the energy of the shot and, accordingly, the recoil force that the sight must endure without consequences. It is the maximum allowable energy of the shot (muzzle energy) that in this case is the main criterion for classifying the sight into one of the categories: light pneumatics, rifles and shotguns, large caliber. It is worth saying that such a division is somewhat arbitrary — see details in separate paragraphs; here is their detailed description:

— Lightweight pneumatics. Sights designed for weapons that practically do not give recoil — such as air PCP rifles, spring-piston “breaks” with muzzle energy up to 7.5 J, carbines chambered for Flaubert, as well as airsoft drives. Such models are definitely not suitable for firearms: they do not tolerate even the recoil from small-caliber rifles, not to mention more serious use. And even pneumatics have their limitations — in particular, powerful (more than 7.5 J) spring-piston models give significant returns with strong vibrations, and in pistols with the Blow-back system, noticeable concussions occur not because of the shot itself, but from -for the work of automation. So it is better to equip these types of weapons with more durable and reliable sights.

— Rifles and shotguns. Sights that can be used with...rifles of small and medium calibers, as well as smoothbore weapons (shotguns). They have a solid construction that allows them to endure rather strong recoil and accompanying vibrations without consequences, but the specific restriction on the allowable muzzle energy (and, accordingly, the calibers and ammunition used) may be different. However, scopes in this category are usually able to safely carry at least 2500 J — this is enough for rifled calibers 5.45x39, 7.62x39 and .223, as well as for 12-gauge rifle cartridges with a standard weight of gunpowder. And in many models, the maximum allowable energy can reach 3500 J and even 4000 J (the smallest values \u200b\u200bnecessary for full-fledged use with .308 and 7.62x54R calibers, respectively). At the same time, for reinforced magnum ammunition, as well as for some powerful (though not large) calibers, such a sight may still not be enough.

— Large-caliber. The most durable and reliable sights, designed for muzzle energy of 4000 J and above. Because of this, they can be used even with large-caliber firearms, as well as with some powerful calibers that are not formally large — for example, .300 Win and .338 Lapua Magnum. The specific restriction on muzzle energy, again, may be different, but if you are looking for a sight for a caliber more powerful than 7.62x54R or for reinforced rifle ammunition like 12x76, you should definitely pay attention to this category.

Separately, it is worth noting that “firearm” sights, even quite durable and reliable, are not recommended to be installed on pneumatics with a spring-piston mechanism or a gas spring. The fact is that such rifles have a specific recoil, directed forward rather than backward, moreover, giving sharp vibrations in different directions; and although the force of such recoil is low, it can still adversely affect the sight, which was not originally designed for it.