Type
The type describes the basic principle of operation of the rifle. Nowadays, you can find pneumatics with a
spring-piston principle of operation (with a conventional or
gas spring), with
pre-pumping (PCP), with pumping before each shot (
multi -compression rifles), powered
by carbon dioxide cartridges and with an
electric drive. Here is a more detailed description of each of these types:
— Spring-piston. As the name suggests, the basis of the mechanism in such rifles is a spring-loaded piston moving in a cylinder. The weapon is cocked manually (usually by a lever or a broken barrel), while the piston is retracted and fixed, the cylinder is filled with air, and when the trigger is pressed, the piston is released and moves forward under the action of a spring, pushing air from the cylinder into the barrel. Rifles of this type have simplicity and reliability of design, low cost, unpretentious maintenance, as well as ease of repair and tuning; they are considered an perfect option for beginner shooters, as well as for lovers of entertaining "shooting" at short distances, there are also models for airsoft among them. It is also worth mentioning the excellent repeatability of shots (with each cocking, a strictly defined portion of air enters the cylinder) and insensitivi
...ty to heat and cold. On the other hand, such rifles require cocking (and most often reloading) before each shot, which can be quite tedious; and the operation of the piston mechanism creates a specific recoil, which adversely affects accuracy and makes it difficult to select optical sights (requires special optics, originally designed for this application). In addition, pneumatics of this type cannot be kept charged for a long time — with prolonged compression, the mainspring loses its properties.
— With gas spring. According to the general principle of operation, rifles of this type are similar to the spring-piston ones described above. The difference lies in the fact that instead of a conventional metal spring, they use a sealed reservoir with a special gas, which plays the role of a spring — shrinking when cocked and expanding when fired. This design has a number of advantages over conventional spring-piston. Firstly, the whole mechanism is much smoother and quieter, and the recoil is softer, which improves accuracy and simplifies the selection of optics. Secondly, the gas spring does not change its properties as it wears out, and such weapons can be stored even in the cocked state. Third, repairs and maintenance for gas springs are less frequent and less expensive (in terms of the number of shots between workshop visits). The disadvantages of rifles of this type, in addition to the need to cock the spring before each shot, include a slightly higher cost than that of classic spring-piston rifles, as well as sensitivity to cold: when the temperature drops, the gas pressure in the spring decreases, which worsens efficiency.
— PCP (pre-pumping). The energy source in rifles of this type is a built-in reservoir containing air (or other gas) under very high pressure — about 200 or even 300 atmospheres. Such a reserve is enough for at least several dozen shots, and a compressor, a scuba cylinder or a special high-pressure pump can be used to fill the tank (sometimes such pumps are even supplied as a kit). In general, PCPs are considered the most advanced type of pneumatics, and these are the rifles used by professional hunters and sportsmen. This is primarily due to the fact that such a design allows you to achieve a very high speed of the bullet, and the recoil is almost imperceptible — all this allows you to accurately shoot even at long distances. On a fresh gas station, the rifle gives excellent repeatability of shots; however, as the gas is consumed, the initial velocity of the bullet decreases, however, in advanced models, a gearbox may be provided to compensate for this phenomenon (for more details, see “Air supply by the gearbox”). PCP pneumatics can be easily multi-shot and provide very simple and convenient ways to feed the next bullet into the barrel. The main disadvantage of such rifles is the high price.
— Multi-compression. Another variety of rifles with a built-in reservoir; however, unlike the PCPs described above, the reservoir must be inflated before each shot. To do this, the design provides for a built-in pump controlled by a lever or other similar device; to pump enough air, usually, you need to make several movements. In such rifles, there is practically no recoil, while they are noticeably simpler and cheaper than PCP pneumatics, but they are inferior to it in terms of power. In addition, pumping up the tank before each shot is quite a tedious task; and the volume of air supplied to the tank at each filling (and, accordingly, the working pressure in the tank) will depend on the number and amplitude of movements made by the pump lever. On the one hand, this allows you to adjust the power directly “on the go”: for example, for a short range where maximum bullet speed is not required, you can not fully pump up the rifle in order to save energy. On the other hand, the actual volume of air and the pressure in the tank will be somewhat different with each recharge, even with the same number of lever movements. This negatively affects the repeatability of shots. Due to this combination of features, multi-compression models are not very popular nowadays, and their purpose is mainly recreational shooting.
— Gas balloon. A type of pneumatics powered by interchangeable cartridges of gas, usually liquefied carbon dioxide. As in PCP, such a tank allows you to make a lot of shots — even a traditional 12-gram can is usually enough for several dozen; and some models use 88g carbon dioxide containers. At the same time, the rifles themselves are cheaper than PCP, but they have less power. It is also worth noting the rather specific characteristics of carbon dioxide as an energy source. On the one hand, it maintains working pressure for quite a long time — it does not decrease as long as carbon dioxide remains in liquid form in the cylinder. On the other hand, the actual gas pressure depends on the ambient temperature, and the initial velocity of a bullet for such pneumatics can change markedly even with daily temperature fluctuations. And of the unambiguous shortcomings of such rifles, it is worth noting that for them you have to buy not only bullets, but also gas.
— AEG (electrically driven). Pneumatics that uses an electric motor drive as a power source. According to the design of the working mechanism, it is similar to the spring-piston mechanism — the basis of this mechanism is a cylinder and a spring-loaded piston. However, the piston in this case is not retracted manually, but with the help of the mentioned electric motor. For the shooter, this means, first of all, that the rifle does not need to be cocked due to muscular strength — for a shot, it is enough to press the trigger, the rest will be done by the electric motor. In addition, in such pneumatics, automatic firing mode can be provided without problems (see below). Note that for a number of reasons this principle of operation is practically not found in traditional pneumatics, but it is very popular in airsoft models; such rifles (“drives”) often copy real military weapons.Magnification
The degree of magnification provided by the rifle's complete optical sight; for models with variable magnification, the entire adjustment range is indicated, for example 3 – 9x.
For sights of this type in general, see "Aiming Device". And several points depend on the degree of increase at once. On the one hand, a higher magnification allows you to better see small and/or distant targets and facilitates high-precision shooting; on the other hand, it limits the angle of view and significantly affects the cost of the sight, and sometimes also its dimensions and weight. And since air rifles are mostly not designed for long distances, the magnification of complete optics in them usually does not exceed 9x, and one of the most popular options is 4x. However, there are exceptions: in powerful high-end pneumatics, you can find sights with a maximum magnification of 24x and even higher.
Actually, the manufacturer most often selects the magnification of optics for the ballistic characteristics of the rifle. So, when choosing this parameter, it often turns out to be secondary, and it makes sense to focus primarily on the muzzle velocity of the bullet and the firing range for which the weapon is designed — usually, the capabilities of complete optics are quite enough for this. It is also worth mentioning the variable magnification sights mentioned at the beginning, which are quite common nowadays — they are somewhat more complicated and more expensive than fix...ed optics, but they allow you to adjust the magnification to the specifics of the situation.
Lens diameter
The diameter of the front lens (objective) in the optical sight, which is equipped with a rifle.
For sights of this type in general, see "Aiming Device". And the diameter of the lens depends primarily on the amount of light entering the scope. Thus, other things being equal, a larger front lens produces a clearer and brighter image; this is especially noticeable in low light. On the other hand, a larger lens is noticeably more expensive, and it also affects the weight and dimensions of the sight; and in bright daylight, the difference from the “smaller” optics may not be fundamental. In addition, recall that the actual image quality is determined by a number of other factors; as a result, high-end optics with a relatively small front lens may well be more effective than a large low-cost model.
In view of the foregoing, it is worth paying attention to the diameter of the lens in cases where the sight is planned to be used in low light conditions — in a dense forest, at dusk, etc. In this case, it is worth considering not only this indicator, but also other features of the optics (and it is best to focus on practical reviews). If the rifle is bought for recreational use in the daytime in good light, the size of the lens will be a purely reference parameter: in such conditions, almost any optical sight works normally.
