Pumped air guns: compression, multi-compression, PCP air guns and rifles

And again we will delve into the theoretical foundations of air guns. This time everything will be much shorter and with examples. More recently, we looked at the general principles of the design of any pneumatic weapon, where there was a mention of the main division of pneumatics according to the principle of operation:

• Spring-piston systems
• CO2 systems
• Pumped systems

The first two categories cover most of the market. Any pneumatic line begins its journey with them, and hardball players go to the enemy with them. Today we’ll talk a little about another world, we’ll look at pumped air guns.

Pneumatics with pumping are obviously considered to be the highest class of pneumatic weapons, and this is evidenced not only by the high prices for the offered samples. Pneumatics with pumping reduce the cost of a shot to the limit, allow you to make truly powerful weapons with a high initial speed, have greater accuracy, and are distinguished by the absence of recoil; there are many models designed specifically for hunting and sport shooting.

The main categories of weapons in this class:

• Compression pneumatics
• Multi-compression pneumatics
• PCP pneumatics

Let's try to understand each category, look at the principles of operation, and also get acquainted with some interesting weapons.

Compression weapon

According to the diagram shown, a piston, driven by a lever, increases the pressure in the reservoir. Pulling the trigger opens the firing valve and gas expands into the barrel. The key difference from the next type is that the lever is cocked only once, which is due to the internal design.

The known samples on the market are mainly represented by compression pneumatic pistols; rifles are still more profitable to make using other designs. Air injection, as a rule, occurs here using a special lever located under the barrel. But there are also exceptions.

Gamo PR-45

Just an exception to the previous rule. The Spaniards chose to keep the combat look of the pistol, but use a compression design - the bolt acts as a lever. As a result, among the compression boots we got something average in orientation and low in price. The pistol cannot be classified as a hunting pistol due to its low power (initial shot speed - 120 m/s half a gram), it is not an entertaining pistol - only one shot per charge, it is not a sports pistol - it does not have the excellent accuracy of pumped air pistols. Something in between, but with a completely combative look.

IZH-46

And this is a domestic compression sports pistol. Classic sports IzhMech. Nothing special, but one of the most famous representatives here in Russia.

Effect of temperature on pressure in a CO2 canister

Temperature affects the CO2 pressure in the can, and therefore the initial speed of the bullet. It is possible to obtain a “golden mean” with optimal environmental conditions. In summer, the efficiency of the “air” will be higher than in winter.

Example:

shooting from a gas pneumatic at +25 degrees Celsius, the pressure inside the CO2 cartridge will be 63 bar, and at temperatures below 0 - no higher than 34 bar.

In addition, at the moment the weapon is fired, for a split second, there is a natural drop in pressure in the container: carbon dioxide expands and becomes a little colder. However, after the atmospheres have equalized, the temperature of CO2 returns to its previous values ​​- it heats up. Single shooting from a gas pistol or rifle is recommended.

Multi-compression weapon

Unlike the previous category, air injection, due to the design, can be carried out in several strokes. So the power itself can be adjusted by the number of strokes, and the maximum limit increases significantly.

Crosman 1377C

And this is, perhaps, the world bestseller in the class of multi-compression pneumatics. The lever is located under the barrel and produces a 180 m/s bullet. A true legend from the world of American pneumatics.

Crosman 2100 rifle

Once again the Crosman representative. Inexpensive, popular multi-compression rifle. The lever, as in a number of other rifles, imitates the forend. The rifle is designed for a maximum of 10 swings, providing a muzzle velocity of 221 m/s. An interesting feature is that the manufacturer has equipped this rifle with a hopper for 200 BB-type balls, while ordinary bullets are fed one at a time through the charging window.

Zoraki HP-01 Light/Ultra

An air pistol from Turkey, also of a multi-compression type. It is produced in two versions – Light and Ultra, differing in barrel length (181.5 and 260 mm, respectively).

The reservoir and barrel are located inside the receiver. The lever is the cover of the receiver with the barrel. In the Light version, 3 shots are made, in the Ultra - 4. The pistol does not use magazines, the bullet fits directly into the barrel. Speed ​​indicators for Light / Ultra models at:

• 1-fold injection of the reservoir - 118 m/s / 126 m/s
• 2-fold pumping of the reservoir - 160 m/s / 172 m/s
• 3-fold pumping of the reservoir - 185 m/s / 200 m/s
• 4-fold pumping of the reservoir — — / 221 m/s

We don’t look at low speeds, we should understand that the shot is fired with a half-gram bullet, and this in muzzle energy will be slightly higher than that of the gas cartridges we are used to.

The model itself is very interesting and worthy of detailed study. But this time the format is a little different.

Types of pneumatic cylinders

There are 2 types of pneumatic cartridges available for sale, by volume:

• 12 grams – enough to fire 55-60 shots;
• 88 grams – this pressure is enough for 400+ shots.

The first type is often used in air pistols, and the second in rifles. Locally produced cans are better suited to Russian pneumatics, while Western ones are better suited to imported ones.

The composition of carbon dioxide in the cans is different:

• gas only, 12 g;
• gas 12 gr. + 10%;
• CO2 with lubricant.

12 gram containers are standard. Samples of 7 and 8 grams are also sold. Grease cylinders are used when it is necessary to quickly lubricate the working parts of an air gun.

Weapon companies produce their own samples of carbon dioxide containers. Despite their versatility, it is recommended to use the appropriate brand for pneumatics: cylinders are designed for rubber seals and weapon model mechanisms.

PCP air guns

The pinnacle of pneumatic development is pre-charged pneumatic guns (Pre-Charged Pneumatics), or more simply PCP.

Air is pumped into the tank in advance using a compressor or a cylinder with a filling station. Unlike previous models, the PCP can fire several powerful shots at once from pre-pumping (depending on the 30-150 model). PCP air guns are divided into:

• Direct-flow - air from the tank, when dosing the combat valve, is immediately supplied to the barrel. With each shot, the pressure drops, speed and accuracy decrease. To monitor the residual pressure in the tank and make adjustments, owners use pressure gauges on the tank. More than suitable for hunting and recreational shooting.
• Gearbox - a gas reducer is installed on the way to the barrel, which ensures stable gas pressure. The pressure in a special tank is lower than in the general one. When the pressure in the common tank drops below the level behind the gearbox, the rifle begins to operate as a forward flow.

It is clear that using high-pressure pre-pumping schemes it is possible to create super-powerful pneumatic models, but we should not forget about the increase in the final cost of the weapon. Moreover, you will have to overpay not only for the technology, but also for a pump or cylinder with a filling station, as well as optics for long-range shooting, for which PCP is excellent.

Hatsan 44-10

One of the most popular, and at the same time one of the cheapest (in the category up to 20,000 rubles) air rifle based on the PCP from Hatsan. A 10-round Turkish carbine that allows you to fire up to 30 shots from pumping.

Crosman Benjamin Marauder

Classic rifle with a wooden stock, magazine for 10 bullets. An interesting offer in the category up to 30,000 rubles.

Of course, there are other more expensive rifles. In the budget for 50 thousand rubles. Interesting representatives from Russia are appearing, but inexpensive models are still more popular. Don’t forget about the most famous pneumatic models, for which special “whales” were developed to convert them to PCP.

Crosman 1377 PCP

And again model 1377. Now this is a pre-pumped air pistol. It is not available in its pure form in the PCP version, so you will have to sort it out a little by hand. The set is installed at once - a reservoir, a receiver, a butt, turning it into a full-fledged carbine.

A matter of minutes: choosing an air rifle

Photo by Alexander Kudryashov.
Pneumatic weapons, at least in Russia, are most often used to hit small targets, and therefore such an indicator as good accuracy is of great importance.

In the USA, air rifles are produced in large calibers, up to .50 inclusive, and are powerful enough to shoot large animals, such as bison.

However, the circulation of such weapons is not regulated in any way.

In fact, it is not a weapon at all.

It can be used as you please, equipped with a silencer and even made fully automatic.

“Thanks to” legislation, it makes no sense for us to produce weapons with a caliber of more than 9 mm, and it is impossible to hunt large animals with them, which is why practicing hunters take weapons mainly of 22 caliber.

Read the material “Quiet and powerful: registration of pneumatics is just around the corner”

Hunting for small targets puts the hunter within certain limits. Thus, practice has shown that the maximum accuracy of weapons should not be more than two arc minutes (58 mm per 100 m).

Since pneumatic shooting is rarely carried out at a distance of more than 50 meters, the specified accuracy is more than sufficient in practical terms.

On the other hand, if the rifle is needed as a training weapon, it is desirable that it produces an accuracy of about one arc minute, which will allow the owner to train and monitor his progress.

Most novice shooters, even from a point-blank range, achieve accuracy within two to three minutes of arc. Having filled their hand, they approach the border of one minute of arc, but this can take more than one month.

In general, a good air rifle allows you to train a lot and constantly.

Here we need to make a small digression to explain what a good air rifle means. Recently I came across the opinion that you can train with spring-piston pneumatics.

Unfortunately, practical experience, and not only mine, has shown that SPP can be used as an entertainment weapon. You can hunt with it, especially if the shot distance does not exceed 30 meters, but you can train only up to a certain point: until the shooter’s performance becomes better than those same two or three minutes of arc.

Read the material “The Russian Guard will register owners of low-power pneumatic weapons”

In addition, with their reverse recoil, spring-piston air rifles kill sights, which turn into consumables, which is inconvenient and, at times, expensive.

Of course, you can shoot from powerful SPP rifles further than 30 meters, but hitting the target in this case will be random. Those who claim to shoot effectively at 50 meters or more admit that they often do not hit the first time, and this is a sign of unstable accuracy.

If we want to train with air rifles and guns, we will need a more accurate and stable tool. Today it is PSR pneumatics, which allows you to get several dozen shots with the given parameters on one charge.

At the same time, the shape of the rifle is almost identical to the firearms.

Having decided to find out in practice what a PCP rifle can give us, we tested one of them in 22 caliber from . The Ataman M2 rifle has a walnut stock, shaped very similar to the stock of a sniper rifle.

All parts and components of the weapon are metal, the cylinder can withstand pressures of up to 300 bar and is equipped with a reducer. In general, a gearbox is needed to obtain shots of uniform power,

The usual standard for a PCP is considered to be the ability to fire from 40 to 60 shots; this quantity is sufficient for any hunt. For training or recreational shooting, high-pressure cylinders are used.

Read the material “Choosing air guns for hunting”

Unfortunately, no household cylinders are suitable for refilling a rifle, so when purchasing a weapon you will have to take care of purchasing a special cylinder. The balloon itself is inflated with a special compressor. You can inflate the rifle with a high-pressure pump, but this is a difficult and time-consuming process, but with such a pump you become completely autonomous.

So, our goal is to shoot the rifle at the range, in ideal conditions, try to get the best possible result and see what the rifle is capable of. Moreover, no matter how many series of shots we make, it is the best of them that will show the capabilities of the weapon.

And one more note. Series of 10 shots are very difficult to execute. For example, I rarely manage to complete them without interruptions. Three or even five shots are successful, but ten are not always successful. And yet, thanks to the greenhouse conditions of the test - shooting from a table with two rests and in a warm room - we will try series of exactly 10 shots.

As mentioned above, shooting was carried out from two rests: from the front hard one, with a small bag of sand on top, and from the rear massive sandbag. This combination made it possible to minimize the shooter’s influence on the shooting result.

What did the shooting show? First of all, a full charge of air is enough for 43–45 shots, after which the pressure in the cylinder drops to 130 bar and the manufacturer recommends charging the weapon.

If the pressure drops below 100 bar, then the gearbox stops working and the rifle turns into a “direct-flow” rifle, that is, it does not stop shooting, but each next shot is weaker than the previous one, and here there can be no talk of any stability.

As for accuracy, it turned out to be up to par. We managed to assemble two groups with an accuracy of slightly less than one arc minute. This suggests that the rifle is suitable for training and gaining experience in handling precision weapons.

Such a rifle makes it possible to shoot on a small range, thanks to which all parameters are worked out, such as working with the trajectory, making corrections for the distance to the target, and working with the wind.

In general, when shooting at a distance of up to 80 meters from an M2 air rifle, we will calculate the correction parameters for both range and wind drift, similar to if we were shooting from a .308 caliber rifle at a distance of 600 meters.

Read the material “They want to take control of all pneumatics”

Considering the lack of available ranges of such a distance (a shooting range with a shooting distance of 80 meters is much easier to find) and the difficulty of organizing such shooting, we can safely say that an air rifle becomes a good training weapon.

We tried shooting without a rest, and only with a front rest, and, I must say, we found such shooting very comfortable. Accuracy has become worse. When shooting with a front stop, it spread to two arc minutes, which, as we found out earlier, is suitable for hunting.

It should be noted that such experiments do not relate to the rifle itself; most likely, they show the shooter’s abilities.

The rifle can be equipped with a magazine for 10 bullets. In this regard, there is an opinion that charging through a magazine can worsen accuracy, but not everyone agrees with this. Most shooters do not use a magazine in competition.

We shot both with and without the magazine and didn’t notice any difference. The magazine has a spring that must be “cocked” by twisting the magazine. The rotation of the magazine has nothing to do with the shot and occurs only when the feed bolt moves.

Read the material “Where and at whom can you shoot with a traumatic weapon”

The manufacturer warns that you should not move the shutter back and forth, as untrained users sometimes do. For example, a shooter loaded a rifle, but the shot was canceled, then the shooter opened the bolt, while the drum turned and placed the next bullet on the feed line.

A second bullet fed into the barrel can lead to jamming and a long procedure for removing and cleaning the barrel.

The price of a high-quality M2 rifle is not inferior to firearms of well-known brands and costs 77 thousand rubles. In addition, you need to add the cost of the scope, cylinder and filling station (high pressure hose with valve and valve). The result will be one hundred thousand rubles.

What are our conclusions? As the test showed, the weapon is well suited for training, allows you to acquire the necessary skills and abilities, and teaches you to work with adjustments for distance and wind.

However, its price is high and significantly exceeds the cost of other types of air guns and small-caliber rifles. But if with other types of pneumatics everything is more or less clear, their accuracy does not meet our requirements, then it’s worth talking about a small-caliber rifle separately.

We hope to talk about the strengths and weaknesses of small guns in relation to PCP pneumatics in one of the following articles.

Alexander Kudryashov April 17, 2022 at 08:53

Does the pressure in the cylinder change depending on its volume?

Inside pneumatic cartridges, carbon dioxide is in different states:

• liquid – 80% (of the total volume);
• gaseous – 20%.

During firing, liquid gas instantly (in small quantities) turns into a gaseous state, filling the free space of the can. The pressure and speed of the bullet will remain constant until all the carbon dioxide is completely converted into a gaseous state. The decrease in pressure in the container will be visually barely noticeable.

According to some pneumatic enthusiasts, Western cylinders contain more carbon dioxide than Russian ones - this is a myth. All 12 gram containers, regardless of the country of production, contain a volume of CO2 equal to 6 atmospheres. The size of the canister and the amount of carbon dioxide in it will not affect the pressure. Changes will follow in several cases:

1. CO2 has completely changed into a gaseous state.
   If even a drop of gas is contained inside the cylinder, a drop in pressure and projectile speed are excluded.
2. The permissible temperature threshold has been exceeded.
   If a pistol or rifle is fired at a temperature between +5 and +31.2 degrees Celsius, the pressure and speed of the bullet will not drop.

How many atmospheres are there in reinforced cylinders?

The difference between reinforced CO2 cartridges and regular ones is their high shot power. The initial speed of the bullet will also increase, almost doubling.

Reinforced and conventional containers do not differ in weight or volume. The secret to increasing the power of shots is the use of a special composition - inert gas. The bullet is given more energy, its acceleration increases. The projectile is capable of penetrating a sheet of metal no more than 0.7 mm thick.

Rules for storing gas cartridges

It is important to properly store gas cartridges for pneumatic weapons:

1. Do not heat the container.
   At a CO2 temperature of more than +55 degrees Celsius, it can provoke a spontaneous explosion of the cylinder.
2. The room must be ventilated and dry
   . The storage area for cans should be ventilated and with low humidity. Avoid exposure to direct sunlight.
3. Restrict access to cylinders for children.
   It is important to ensure the safety of your small family members - store pneumatics and related items in a gun safe, and separately.
4. Gas canisters must be used for their intended purpose.
   Products intended for pneumatics are used in this type of weapon.
5. Do not store gas-cylinder pneumatics in a charged state.
   A punctured can must be shot out to the end. Depending on the manufacturer, loaded weapons can be stored for no more than a day, but preferably no more than 4 hours. Ignoring this rule will lead to damage to the rubber seals.

Prohibited

remove a completely unfired gas cylinder from the pneumatic gun to avoid damage to the gaskets.