All you need to know about Air Rifles

1. Springguns

Spring rifles (Springers) are air rifles that use a piston driven by a spring. The spring is tensioned by buckling and bending the barrel until a click is heard. You then put a pellet in the kinked barrel and straighten it again.

The most well-known air rifles are spring rifles (Springers). These are rifles that use a piston driven by a spring. By fully 'buckling' and bending the barrel until you hear a kink, you tension the spring. Then you put a pellet in the kinked barrel and straighten it again. Because of this kink, the rifle is also often called a kinked barrel rifle or articulated rifle.

The Webley VMX Classic - Spring rifle with normal spring

Shooting position

So, when firing, the rifle moves back and forth due to the mechanical movements of the spring and piston. Most rifles are made so that a good shooter can keep the rifle in one place during this movement and aim it properly at the target. It is important to teach yourself a posture that ensures that the recoil of the rifle always has the same effect. Consistent training and practice makes perfect and so also in this case. This is obviously relevant for people who enjoy improving their skills in order to compete in matches or competitions, for example. When you learn to shoot well with an air rifle, you can generally shoot other types of rifles as well, so you don't just increase your skill at one type of rifle when practising with a spring rifle.

Recoil

Most shooters are generally recreational or occasional shooters. That means you probably invest less time in practising shooting but simply shoot for fun. Some spring rifles have a rather violent recoil which makes it difficult to hit the target. This can lead to situations where fun turns into frustration and the rifle is eventually put away. Especially the better air rifles have a less severe recoil. Competitions in the Netherlands use more accurate and less powerful rifles. These are often a lot more expensive than the average rifle used for recreational shooting. These rifles use a mechanism that reduces the recoil and are often equipped with a bottom or side tensioner (instead of a rifle barrel).

Force

Powerful articulated rifles are generally sold to people who like power more than accuracy. Many recreational shooters choose such a rifle and enjoy the bang produced when a pellet reaches the speed of sound. These rifles are often powerful, not very expensive and popular among younger shooters. These rifles are fine for recreational shooting where one shoots at cans or larger cards. However, it is more difficult to get great precision and accuracy out of a shot with these rifles.

Lower side tensioners & Nitron piston

Most shooters willing to practise can get a lot of enjoyment out of a spring rifle. However, these are often the slightly more expensive and better spring rifle models such as those from Weihrauch. Spring-loaded rifles have a fixed barrel which, by definition, makes them slightly cleaner than rifles with an articulated barrel. Some spring-loaded rifles have a gas spring. Here, the rifle is not driven by a spring but by a kind of gas balloon. The principles of the systems are the same but the recoil created is significantly reduced by the absence of a spring and piston. In addition, the gas spring does not slacken like a steel spring does when under tension for long periods of time. Partly because of this (and for safety reasons), it is not wise to put a rifle away under tension. Despite all these points, shooting with a spring rifle is quite tricky. If you teach yourself to shoot with the correct posture, you will see that your ability to hit the target will increase considerably.

Above: Classic spring. Below: Nitron piston system.

2. Co2 and pump guns

For recreational shooting in the garden or at shorter distances, Co2 and pump shotguns are perfectly suited. These guns often have a slightly lower muzzle velocity of around 210 m/s for Co2 and up to 245 m/s for pump guns.

Co2 compressed air rifles

When using Co2 compressed air rifles, there are a few things to bear in mind. A Co2 cartridge is under a pressure of 60 bar on average at 25 degrees Celsius. When it is colder outside, the cylinder pressure may drop. At 12 degrees, for example, the pressure will be around 50 bar. What further affects the pressure of the Co2 cartridge is the cooling that takes place when shooting. The Co2 cartridge cools down considerably by evaporation. The pellets fired in quick succession will therefore arrive a little less hard and lower on the map each time. After waiting for a while, the Co2 cartridge will return to temperature and can be fired with full power. This deviation (when shooting in quick succession) can be frustrating for an inexperienced shooter. At average temperatures, you can shoot well with a Co2-powered rifle. The more expensive Co2 rifles, often suitable for competitions on a 10-metre course, have a regulator installed to keep the pressure constant. The principle of a Co2 rifle is almost identical to that of a PCP rifle.

Walther Hammerli - very accurate Co2 rifle

One advantage over PCP rifles is that Co2 rifles are often a lot cheaper because you don't need a pump or a compressed air cylinder. However, you do need Co2 cartridges, which you should purchase depending on how much you plan to shoot.

Co2 cartridge - 12 grams Co2 cartridge - 88 grams

Pump shotguns

The pump shotgun used to be a very well-known and popular rifle because of its low recoil. Nowadays, the pump shotgun is rare after the emergence of the compressed air shotgun. For many people who have owned one, it is a legendary model; unfortunately, there is very little development in pump-action rifles today. This does not mean that the rifle no longer has any fans.

Benjamin Sheridan (1947) - Legendary pump shotgun

The pump shotgun is equipped with a fixed barrel and can be inflated via an underspanner. The pressure can be dosed by the number of times you inflate the rifle. So, in a sense, you decide how hard you end up shooting. This has its advantages when you are dealing with different distances and want to change the trajectory of the bullet. The other side of this system is that it can lead to confusion for inexperienced shooters, making it harder to learn the weapon. This causes many people to mistakenly think the rifle is unreliable. In addition, the rifle fires a single shot per charge. This means that after each shot, the rifle has to be re-inflated.

3. Compressed air rifles (PCP)

Compressed air rifles use compressed air under high pressure to drive a pellet.

Webley Raider 12 - high-quality PCP rifle at an affordable price

When you pull the trigger, a hammer is released in the mechanism. This hammer strikes a pin which then opens a valve. Opening this valve causes compressed air to blow the pellet out of the barrel. The valve opens briefly and then immediately closes again due to the pressure applied to the air cylinder. This air tank is often located under the barrel of the rifle. The tank is filled to a pressure of between 200 and 300 bar. When shooting a bullet, there is no noticeable recoil. Due to the mechanism, the rifle shoots almost silently and without vibration.

Hand pump & diving cylinder - Different ways of filling the PCP rifle

The compressed air tank is filled with a hand pump or a diving bottle (compressed air cylinder). The hand pump is very similar to a bicycle pump, however, it can generate a pressure of about 250 bar. High pressure is dangerous, so caution is required in all cases when handling it. Materials and products should be of high quality. Diving tanks should be inspected regularly. You can only tinker with such a tank when it is completely empty and disconnected.

A PCP rifle is made so that the energy output remains constant to some extent when you shoot. It may be that when the pressure in the tank decreases, the power of the shots also decreases, causing the bullets to end up lower on the card than intended. This in some cases makes PCP rifles less stable than a good spring rifle that releases a constant force.

Pressure regulator - Gives a constant amount of pressure every shot

Newer compressed air rifles are equipped with a regulator that controls the pressure. The air is regulated from the tank through an intermediate reservoir, this ensures that the same force is fired with every shot. In older PCP rifles, you can still fit regulators. The handy shooter could do this himself, otherwise you need to go to a gunsmith who will do this for you. Regulators are a fairly recent development in the world of PCP rifles. They are now available for almost all PCP rifles that do not already have a regulator. PCP rifles are easy-to-use weapons that can shoot very accurately. This makes the rifle very suitable for the shooter who wants to shoot cleanly. With the use of a good scope, you can easily hit a penny at 30 metres.

AGS rifle scope 4-16x50 IR Cobalt Scope with mildot and illuminated cross

What makes PCP rifles so popular and well-loved is the fact that they can be shot with a magazine. So that means you can fire shot after shot with relatively little effort where you only use a bolt to push the bullet through into the chamber. This is very similar to shooting, say, a shotgun or other bolt action rifles. Most magazines hold between 8 and 10 bullets, depending on the calibre of the rifle. In addition, with an average PCP rifle you can fire up to 80 shots with a full tank (50 on average) the exact amount of shots that can be fired always depends on the type of rifle.

Magazine for PCP rifle

The Netherlands has no limit to the power of an air rifle. This force is generally measured in the unit Joules. This unit represents the kinetic energy created when an object of a certain mass (M) is fired at a certain speed (V). The resulting energy is measured and expressed in Joules (J).

Generally, many air rifles list a muzzle velocity and a number of Joules. Note that these values are measured with a pellet of a specific weight. If you use a pellet that is, for example, heavier than that of the original measurement, you will measure a lower muzzle velocity but a higher amount of Joules.

Using the link below, you can calculate how much energy and speed your rifle achieves when using different pellets.

Joules Calculator

Maximum power of an air rifle in the Netherlands

As mentioned, the Netherlands has no limit on the amount of energy that can be produced by an air rifle. Average spring rifles shoot between 15 and 24 Joules. PCP rifles are often between 35 and 45 Joules. There are also extremely powerful PCP rifles available. Some of these can reach energies as high as 600 Joules. These PCP rifles often shoot with larger pellets than many shooters are used to. Think of sizes such as 6.35mm, 9mm and 12mm. Rifles with a muzzle velocity higher than 330 m/s can reach the speed of sound with the use of the right pellet. As soon as the pellet passes through the sound barrier, you will hear a loud bang. Just remember that breaking the sound barrier can make the pellet trajectory unstable.

Silencer: Environment

The sound produced by an air rifle can be very loud and therefore scare people and animals. Many compressed-air rifles are therefore equipped with a silencer. Because the system of a compressed-air rifle makes little noise, you only hear the bang of the air leaving the barrel. This can be excellently muffled so that only a soft whispering "blop" sound can be heard. Various types of silencers are available for compressed-air rifles. On some compressed-air rifles, the barrel is already fitted with a silencer, which is then incorporated into the barrel itself by means of a kind of casing that can be seen around the barrel.

Hatsan AT44-10 Tact QE - PCP rifle with built-in silencer

Silencer: the mechanism

The mechanism of a silencer is that the pellet is passed through a sequence of chambers. In this way, the extra pressure behind the pellet is given the opportunity to be gradually reduced through the chambers. The concatenation of chambers also ensures that the pressure is gradually distributed, which also allows the drive air to gradually flow out.

Ambient noise

It is important to take people and animals in your environment into account when shooting. You obviously don't want to cause unnecessary nuisance and should therefore be well aware of what kind of noise a rifle produces when using it. The noise a gun makes can therefore be a decisive factor when you want to buy one. Cheaper spring-loaded rifles often do not come with a silencer as standard. More expensive models that also have a gas spring are often equipped with a silencer, which makes the whole thing a lot quieter than normal spring rifles.

GAMO Grizzly 1250 Whisper IGT MACH 1 - Powerful rifle with gas spring and silencer

Extremely powerful rifles

The most powerful rifles in our range include the Gunpower Texan (600 Joules) and the Air Venturi line of rifles (310 Joules). These are PCP rifles that fire a heavy calibre pellet of .45 (11.43mm) or .50 (12mm) under extremely high pressure. These types of rifles easily have a range of 100 metres and beyond. Especially in America and in countries where laws on hunting with airguns are a lot more lenient, these weapons are used for hunting both big and small game. Given the enormous power and size of the calibres, these types of rifles are also very popular among shooters used to shooting firearms or using 100-metre courses. The Air Venturi line has a special range of projectiles that can be fired. Besides standard pellets, arrows and pellet cartridges can also be fired with this PCP rifle. No further modifications on the weapon are required for this.

Air Venturi Dragonclaw .50 Gunpower Texan .45

Spring-loaded and pump-action rifles are usually limited to releasing single shots due to their mechanism. With each shot, the rifle is cocked and you can put one pellet in the barrel each time. Many shooters like this because buckling, reloading and firing becomes a kind of unified procedure that precedes a shot. Reloading the air rifle repeatedly and systematically gives the peace of mind needed for concentrated shooting.

Placing the pellet

Inserting the pellet must be done carefully. Pellets are often made of lead and are therefore soft and easily deformed. On rifles with an articulated barrel, the pellets are pushed into the barrel. With side- or bottom-barreled rifles, the pellet is placed in the barrel after which the locking mechanism pushes the bullet further into the barrel. This same mechanism locks the barrel. Co2 or Compressed air rifles often come with a magazine. Single-shot compressed air rifles, like spring rifles, are loaded with a bottom or side tensioner.

Magazines

Both Co2 and compressed air rifles use a magazine with multiple bullets. This magazine is filled beforehand and then placed in the rifle in one action. When the magazine is empty, you can replace it with another one. In competitions, magazines are often not used.

Pellets & materials

Most bullets or pellets are made of lead. This type of metal has a number of dangerous properties that you need to watch out for. To humans, lead is toxic, so when loading and touching the pellets, you must be careful not to ingest any lead. Lead is also bad for the environment. It is therefore important that pellets are collected by, for example, a bullet catcher and that no bullets are left behind on the grounds. You can simply throw the pellets that have been used away with the residual waste because they are recovered when the waste is processed. You can possibly use a plywood sheet with a thickness of 2cm, but be aware that when you shoot on a straight sheet the bullets can bounce back. It is important to prevent this by, for example, screwing a sheet of lead against the plywood. When shooting on cards, you can use suitable steel ball traps, which often have a size of 14x14CM. These bullet catchers catch the pellets in a tray that can be emptied. These traps work best when you put a small layer of sand in the tray. The pellets can then jump out a little less easily here.

Shooting loose targets on private property requires the targets to be placed in a bullet-catching cupboard. You can also use bullets made of brass, zinc or copper, which are slightly less polluting for the environment.

Pulled barrel

Pulling the trigger is done in two parts. First, you take out the free stroke until you feel resistance. Then you pull the trigger evenly, causing the shot to go off. Later, we will tell you more about releasing the perfect shot. We move on to how the pellet passes through the barrel. Most pellets come in the shape of a diabolo. The back of the pellet has a funnel shape, which is pressed by high air pressure into the helical grooves on the inside of the barrel this is also called a pulled barrel. The pellet seals the barrel with this the rotational movement of the grooves (lowers) and fields (raises) is transferred to the bullet. As the pellet leaves the barrel, it rotates about its longitudinal axis, holding the direction of the barrel in the bullet's trajectory. In rifles that do not have a drawn barrel, the pellet will tilt right after leaving the barrel and deviate from the ideal pellet trajectory.

Safety

When tensioning and loading the rifle, it can be used. For safety, air rifles are equipped with a safety catch. When the air rifle is locked, the trigger cannot be pulled. This is based on the idea that the rifle cannot be fired until the shooter actually pulls the trigger. Often, air rifles come with an automatic lock that automatically sets the safety the moment the rifle is cocked. If this does not happen automatically, it is important that you teach yourself to lock the rifle after tensioning it so that it cannot be fired until you are ready to do so. You must do this even when the air rifle is not cocked and unloaded.

The bullet path

When the pellet has left the barrel it flies freely through the air and there are two forces that cause it to deviate from its direction. First, the pellet experiences resistance from the air it flies through. The bullet slows down due to the resistance of the air. Then, of course, there is gravity that pulls the bullet downwards, this actually causes the bullet to start falling the moment it exits the barrel. A 5.5mm bullet leaving the barrel at about 264 m/s drops 5cm after just 25 metres! At 50 metres, this rises to more than 20 cm. The shooter must correct this deviation with his scope or aiming equipment by calibrating it with the bullet trajectory and distance from the target.

Shooting range & Bullet catchers

With hitting the target, the pellet deforms on impact. Earth, wood and special bullet catchers will hold the pellet after impact. Hard surfaces can cause the pellet to explode, causing pieces to fly around. A pellet can also go off and continue its path at a different angle while retaining a lot of energy. If the pellet lands at a certain angle on a hard surface, it can rebound at right angles into pieces, which can hit the shooter himself or bystanders. This already shows that a shooting range (even on private property) must be properly and safely cordoned off so that no people or animals can stand near it.

We advise everyone to wear safety glasses when shooting. These are glasses specially designed and made for shooting sports. It is very important that you shoot at the intended targets and make sure there is a shelter behind them for bullets that are misfired. Do not choose hard materials as a background at the shooting range such as stone or steel.

1. Terms and definitions

It is necessary to set up a scope after it has been purchased and mounted. You can also call setting the scope zero. The question now is at what distance is it best to set the scope?

Setting the rifle and the distance to be kept differs per rifle and situation, it mainly depends on the situation and the targets being shot. When you are shooting at 10 metres on cards like in the Olympic discipline, it is obvious to adjust the scope to 10 metres. When aiming the cross of your scope at the bullseye, the bullseye will hit. If you shoot at targets spread over different distances you will notice that the point you aim at differs from where your bullet lands.

To avoid confusion, we will first explain some terms. Many terms and concepts about ballistics and shooting sports originated in the English language and therefore do not have a good translation into Dutch.

The aiming point

This is the point or target at which you aim through your scope. Through the cross or mark of your scope, you aim at a certain point that eventually becomes the target of the shot.

The Point of Impact

This is the point at which the bullet eventually lands or where the pellet hits the target. This often differs from what your aiming point was.

The Killzone

The Killzone is the area around the aiming point where the shot can still be considered 'lethal'.

Point-blank

Is the range (the distance from X to Y along the bullet trajectory) in which the hit point lies within the killzone.

Objective

The outermost lens of the scope.

Eyepiece

The first lens of the viewer.

The Optimum Zero Range

Or called Optimum Zero Range (OZR) is the optimal distance at which zeroing works best and within the PointBlank.

When you want to hit targets of, say, between 5 and 50 metres, you come into contact with these concepts. Later, we will discuss the laws of nature relevant to ballistics. To explain this properly, we will use an example rifle. The scope we are going to use for this is an AGS 3-9x40 AO Cobalt Mildot. The rifle we will use is a Webley Raider 12 PCP with a muzzle velocity of 250 m/s. The scope is mounted 3.75CM above the barrel. We could also have used other makes and models for this test.

2. Setting up the scope

When we first start shooting with an air rifle, there are a few things to check first:

• If you are shooting in the backyard, make sure that no people or animals can get into your range.
• Make sure you have a large plywood board hanging that is about 1 metre by 1 metre and at least 20mm thick, make sure the pellet cannot leave the range.
• When the shooting range is set up, you can hang a piece of paper of A4 or A3 size. On this sheet, draw a vertical line of about 20 cm and attach this sheet in the middle of your target plate.
• At a distance of 10 metres from the end of your barrel to the target plate, set up an arrangement with a table or workbench with a laying support on top. You can easily make this yourself by, for example, filling a jute or plastic bag with sand and setting it down on a flat surface. Make sure the height of your run is about as high as the height of your target. Sit on a chair or stool and make sure the air rifle is supported by the leg rest. Cock and load the rifle. Make sure the rifle is locked and therefore on safe!
• Look relaxed through the rifle scope and search with the point at which the image in the lens is optimal. Then focus the rifle scope on the target. (Maximum zoom in, focus with the objective and zoom out to 4x magnification). Press the release allowing the rifle to focus and fire a shot at the target. Repeat this operation twice, eventually revealing three shot holes on the sheet of paper flush with the line you drew. You can now start determining the average deviation.
• The rifle can now be roughly zeroed using your scope's width settings. Remove the protective caps from the elevation and windage adjustment knobs (turrets). The adjustment knobs for horizontal (Left/Right) and vertical (Up/Down) adjustment can be used.

Example:

Your average weft of the group of shots is (for example) 8 cm to the right of the line. Now turn the knob for the width setting 10 clicks to Left.

Now shoot at the target three more times.

See again what the average deviation is on the vertical line. From the difference between the first and the second group of shots, you can calculate how many millimetres 1 click represents.

You do this as follows:

• 1st group of shots 8 cm to the right of the vertical line
• 10 clicks to the left
• 2nd group of shots 5 cm from the vertical line
• 8 - 5 = 3
• 3 : 10 = 0.3
• 0.3 CM = 3 MM

So per click, the viewer jumps 3 mm for a shot at 10 metres.

You can now work out by calculation how many clicks the viewer needs to get to the vertical line.

50 : 3 = 16.67 (rounded 17)

17 clicks you need to get the viewer pretty much on the vertical line (with a deviation of 0.3 mm).

Shoot the chart again and adjust the viewer where necessary!

Adjusting the height of your viewer is done in exactly the same way. Take another piece of paper and now draw a horizontal line on it. Again, shoot three times at the map and adjust the viewer until the bullets touch the horizontal line. If you adjust the viewer's horizontal and vertical lines separately, you can concentrate much better on one part of the adjustment.

You have now zeroed your scope, rifle and the bullets to 10 metres. You can reset the adjustment system by unscrewing the plate of the click system. This plate (with dashes marked on it) can now be set to a fixed 0 point again. You now know that the zero point is set at that position. If you have set the viewer differently for whatever reason, you can always retrieve the original setting!

The viewer is now correctly set to 10 metres, you can now practice shooting at this distance. You will notice that when you shoot at targets that are closer or further away, the bullets will arrive higher or lower. If you start shooting at a different distance, you will therefore have to zero the scope again. Also, when you shoot with a heavier or lighter bullet, it will arrive lower or higher. The weight of the pellet changes the shot because a heavy pellet goes slower, has a shorter bullet trajectory that also has more curvature.

Shooters with little experience will find that the spread of the hit points around the target is quite large. When you start shooting more precisely, you may have to re-zero your scope because you now have no deviation. You will also come up against the deviation caused by the scope's parallax.

3. Parallax

The concept of parallax is quite complex and therefore difficult to explain. Parallax involves a deviation where the object one focuses on seems to move with the background as soon as you change position. In this piece, we are going to explain how this deviation occurs.

You can simulate the effect of parallax by, for example, holding a finger out in front of you and looking at it first with your left and then with your right eye. The finger does not change position but seems to move in relation to the background objects. When you move your eye in front of the lens with a viewer with paralax deviation, the same thing happens. The cross of the viewer moves slightly relative to the object being aimed at. Below is an example of a viewer on board an aircraft.

You can solve this effect quite easily by looking straight through the lens. It is difficult to be sure if your eye is directly in front of the lens. When you look through the lens and you can see black edges around your image, you may be looking through the lens at an angle.

Quality binoculars often have a setting that allows you to focus the target. You do this by adjusting the rear lens of the viewer. These scopes are designed to avoid parallax when the target is in focus and the front lens (Eyepiece) is properly adjusted to the cross in relation to the rear lens (Object).

Parallax in the viewer

The image above shows how room for deviation arises around the cross when the cross is not properly focused on the wire cross. This does not imply that the target you see is out of focus. If the eyepiece (the first lens) is not set properly, you can focus the image while still creating parallax deviation because it is not set properly.

Setting and focusing the eyepiece is difficult. The best way to do this is to fix your rifle in a stand and then check (by moving your eye back and forth along the lens) if there is any parallax deviation. It is advisable to practise this regularly and then at different distances. This will give you a feel for your scope and you will be better able to adjust the parallax for different distances.

4. Red Dot Scopes

The Red Dot is a scope in which an LED is projected onto a reflective piece of glass or transparent mirror, revealing a dot or shape. Because the glass is curved, it reflects straight back to the eye. This red dot is ultimately the indicator that shows where the bullet should land.

A Red Dot (hereinafter RD) is manufactured so that the red/green dot stays in line with the weapon. The diagram above shows this clearly. The beauty of a Red Dot scope is that there is no parallax deviation.

With an RD, it doesn't matter how you look through the lens, as there is usually no magnification with a Red Dot so you can keep looking with two eyes. Focusing the RD is also not necessary and it does not matter how far your eye is from the lens. The RD is mainly used in situations that require fast aiming and shooting such as paintball, hunting or in situations that require a tactical aiming device. You can also equip an air rifle with an RD, which is often less precise than a scope but allows you to find your target faster. In addition, RDs also work fine on an air pistol.

The RD exists in different versions. The simplest variant is one with a hollow mirror a somewhat more elaborate version is an RD that is incorporated in a tube. RDs that are in a tube are often stronger and sturdier than RDs with a single hollow mirror. There are also RDs that do have magnification so you can get closer to the target.

You can get an RD working well on air rifles and can be placed reasonably far from the eye. Because there is no parallax deviation, it also doesn't matter if you look through the RD at an angle. The simple RDs are difficult to set at different distances. In addition, it is often not possible with an RD to correct via mildots as is possible with a scope fitted with a reticle. As a shooter looking for precision and wanting to hit the target at various distances, an RD is therefore less useful than a rifle scope that enlarges the target.

1. Determining the bullet path

The best way to determine the bullet trajectory is to experiment. For example, you can adjust the air rifle to 10 metres. That means that at 10 metres, your pellet hits the aiming point exactly. Then you start shooting at a different distance and aim at the target again. For example, you can start with three shots at 5 metres, then at 10, 15, 20, 25, 30, 35, 40 etc. This depends on how far you eventually want to shoot. Shooting multiple shots at 1 distance ensures that you can eventually determine an average and deviations have less effect.

It is imperative that this is done in a precise manner. For this, it is best to use a large sheet of paper where you draw a horizontal line for each distance. Make sure you get the height of the shot right with your scope. The deviation to the left or right does not matter much because you have drawn a horizontal line.

You hang the sheet of paper at the same height as the rifle. Measure the distances and put a line at each distance or put something down so you know which distance is where.

The final distance is the distance from the mouth of the rifle to the target. When aiming, it is a good idea to keep both eyes open so you can keep a good eye on your surroundings too.

Keeping the rifle still

When adjusting your air rifle, it is important to hold it steady. For example, you can sit at a table and rest the rifle on a sandbag or other heavy yet soft object. The advantage of this is that the bag will absorb the vibrations of the rifle and it also prevents the rifle from lifting when you pull the trigger. Compressed air rifles or rifles powered by Co2 cartridge can also rest perfectly well on a sandbag. When you squeeze the bag, you can easily adjust the height of the shot while the rifle moves minimally. Later, we will cover and explain different shooting positions.

Spring rifles

When using a spring rifle, a sandbag is again not recommended because it must be able to properly release the force of the recoil. If this recoil cannot be channelled through the rifle itself, the shot will be less accurate.

When firing the rifle at different distances, always measure the vertical distance between the bullet's impact and the line you aimed at. If you divide this distance after three shots by the number of shots, you know the average deviation. If you were to put this deviation in a graph then you can get a good idea of exactly how the bullet trajectory goes over a longer distance. Example: At 5 metres, you shoot 1.6 cm too low. In the graph you can then indicate X=5 metres and then put a dot at -1.6. If at 25 metres you shoot too high fill in X=25 metres a dot at 2.7 cm. If you do this for all measured deviations then you can connect the dots by drawing a line between them.

The bullet deviation when it leaves the mouth of the rifle is equal to the height of the scope relative to the barrel. For example, if this is 3.75 cm you can actually enter X=-3.75 at X=0.

Pellets

The trajectory of the pellet is determined by its velocity and shape. In an air rifle, the energy given off per shot is fairly equal. This means that a light pellet has more velocity when fired but, due to its light weight, also loses more velocity as the pellet flies further. The shape of the pellet also has a lot of influence on this. With pellets that are aerodynamically shaped, there is less loss of velocity because its shape encounters less drag. So determining bullet trajectory is tied to the type of bullet you use. A different pellet means calculating your pellet trajectory again.

It is especially noticeable among novice shooters that they can only shoot accurately at one distance. What they often don't fully understand is why the bullet doesn't end up at the desired point at other distances. They don't realise that both the rifle, the pellets and the scope affect the bullet trajectory and that these combined should be adjusted to a specific distance.

As the graph above shows when you zero the scope at 15.4 (or 30.1) metres it creates an area that falls within the Killzone. The space inside the Killzone is about 1 cm (1/2 cm either side) this is on the graph the area between the purple lines. The area that falls within 12.1 to 33.2 metres is called PointBlank. This is the area marked in purple on the graph. You can say that the shooter is shooting cleanly at a distance of 12.1 to 33.2 metres. If the distance is greater than 33.2 metres or shorter than 12.1 metres, the shooter will have to correct to adjust these values. If you shoot at a shorter distance you should already know from your calculations that at, say, 10 metres you will have to aim 0.9 cm higher and when shooting at 5 metres you will have to aim 2.1 cm higher. Handling corrections at short range are covered later in the chapter.

After this, you can use the measurements taken on the range to determine the ideal extreme distance for zeroing your rifle. Professionals call this the "OZR" or the "Optimum Zero Range". For this, you will need a ruler and the graph you just made. Draw a line from the zero point (0) and make sure it intersects the bullet trajectory at a higher point. It is important that the line stays at most 1/2 cm (half the Killzone) below the top (the highest point) of the arc relative to the bullet trajectory. You 'adjust' the reticle higher in your theoretical scope in this way. As the image shows, the optimum distance to zero is now at 15 metres and at 30 metres. You can now start shooting again so that you can zero the scope at a distance of 30 or 15 metres. When you start taking measurements again you can make a again of the bullet trajectory a graph as shown above with a Killzone of 1 cm in it. You can repeat this procedure several times for the best and most accurate results. When zeroing optimally, the distance will still shift slightly compared to previous measurements. This is due to the fact that a deviation of the bullet's trajectory occurs because the bullet shot higher or lower also deviates slightly from a horizontal trajectory. We will discuss this in more detail later.

From this point on, we will use the values shown in the graph on figure "OZR example rifle". What we now know is that the rifle shoots accurately within a margin (Killzone) of 1 cm over a distance (Pointblank) of 12.1 to 33.2 metres where a correction can be done at a shorter distance by aiming slightly higher. These are 0.9 cm at a distance of 10 metres and 2.1 cm at a distance of 5 metres.

2. Point Blank

With a rifle like the one in the example that is optimally zeroed, the scope is as low as possible above the barrel, making the Point blank reasonably large. Here it is only necessary to make an adjustment when you get outside it. You will find in practice that you will only need to make an adjustment when you shoot within 10 or beyond 35 metres. The images below show two example adjustments. In both situations as shown, you will need to aim slightly higher. As can be seen, at 10 metres you will have to aim about 0.9 cm higher to hit the target exactly. At 40 metres, you will have to aim about 3.6 cm higher to get your shot right. The crazy thing is that you have to correct relatively more at a short distance than at a longer distance. This is often hard to understand because it goes against your intuition.

Correction 25 mm at 40 m Correction of 25 mm at 10 m

With all rifles, bullets or scopes, you have an Optimum Zero Range (OZR or Optimum Zero Range) this is the optimal distance to zero. We tackled the way to find the Optimum Zero Range for the rifle you are using in the sections above. The total distance and location of the Pointblank are determined by the height of the scope relative to the barrel. Thereby, viewers with a larger outgoing lens always sit higher than those with a smaller lens as shown in the image below. The variation in point blank takes place in the following way.

Viewers mounted at different heights on the rifle.

• Low: 30mm - PointBlank from 10.7 to 32.1 m, OZR = 12 m
• Medium: 40mm - PointBlank from 12.1 to 33.2m, OZR = 15.4m (Example)
• High: 50mm - PointBlank from 13.4 to 34.4m, OZR = 16.6m

The speed of the bullet

The PointBlank gets longer as the speed increases also the start and end points of the PointBlank shift.

In the example rifle where the scope is mounted at a height of 40mm, the PointBlank varies:

• 200 m/s: 9.3 to 25.8 metres
• 230 m/s: 10.6 to 29.3 metres
• 264 m/s: 12.1 to 33.2 metres (Example)

Shape of the pellet (aerodynamic)

Pellets that encounter resistance from the air are more likely to lose speed. This is noticeable at longer distances because the PointBlank becomes shorter.

For the beginner, it is sensible to buy a rifle with a reasonable standard muzzle velocity of between 220 and 280 metres per second with a scope mounted 30mm away from the barrel. Especially from a tuned PCP rifle you will be able to shoot very well, these are clean over a distance of 10 to 30 metres with ease. These are perfect distances for people with a bit of space around the house! If you want to shoot closer or further away you will have to adjust the PointBlank. Estimating distances is not easy.

You can determine the distance to your target in two ways:

Adjustable Objective

With the viewer's AO (Adjustable Objective, the objective or field lens) you can adjust the distance by determining the number of Yards by turning the lens. Unfortunately, this method is often not very precise. It is best to check and measure all the distances of the AO on your scope. You can then note the actual distances on the viewer by writing them down yourself.

Using the surroundings

In familiar surroundings, you can estimate the distance reasonably well if you are familiar with the distances of other objects in your surroundings.

Mildot on the reticle

It is important to know what distance corresponds to the Mildots (the dots) on your reticle. You can measure this and write down the data about it.

You can easily do this once you know the bullet trajectory of your rifle. We will take the correction of 0.9 cm upwards at a distance of 10m. Make a card with two crosses 0.9 cm apart on it. Place these at a distance of 10 metres and aim with the scope at the highest cross (aiming point). The cross at the bottom indicates the point of impact when the bullet is fired over a distance of 10 metres.

In the example rifle, this was just under 1 point below the crosshair. This way you can calculate the hit point for all distances via the bullet trajectory without having to shoot. The image below shows a correction chart used by shooters during competitions as a reference when they have estimated the distance.

Correction chart

3. Ballistic theory

As covered in previous chapters, the way of finding the Optimal Zero Range and manual is to get to know your rifle and determine what the rifle is capable of. You can also find out what values the rifle has through theory.

We will explain and explore this theory further in this chapter.

The trajectory travelled by a projectile (bullet) is an important physics application that has been used many times throughout history. This application has already been relevant to the effective use catapults, bows and arrows, cannons, muskets and ballistic missiles equipped with warheads. To make the trajectory of such projectiles as accurate as possible, increasingly precise algorithms have been developed over time. This is great because these can be perfectly applied to the trajectory of a bullet from a rifle.

Calculating bullet trajectories is part of a complex field of physics and mathematics. Calculating an ideal bullet trajectory without taking air resistance into account are often questions on school exams. The shape of the bullet and its behaviour as it passes through the air is subject to so many factors that it is difficult to express in formulas. As is customary in science, determining a bullet's trajectory is therefore accompanied by taking measurements that further explain the behaviour of projectiles. With the knowledge determined about this throughout history, software programmes have been created that can accurately simulate bullet trajectories. The well-known manufacturers of scopes and other optics such as Hawke Optics have designed nice ballistic software. The software programmes are available in different versions for both desktop and smartphone applications.

This software programme 4.3.5 (see above) is offered by Hawke Optics for free. You can download this programme at www.hawkeoptics.com. The programme is pre-programmed on well-known Hawke scopes. This software is updated regularly and the smartphone variants are also good to use.

Determining a bullet trajectory requires some data:

• The muzzle velocity of your rifle in metres per second (m/s) or in muzzle energy in Joule
• The calibre and weight of the bullet
• The ballistic coefficient (BC value) of the pellet and form factor (G1 to G7, GS, GA etc.)
• The height of the scope above the barrel.

Velocity and energy

The (muzzle) velocity is the velocity (v of velocity) of the bullet as it emerges from the barrel. As soon as the bullet exits the barrel, it starts to decelerate and is pulled down by gravity. Velocities are expressed in metres per second (m/s). You will also often come across English measurements expressed in feet per second (ft/s) in videos and other data on velocities and rifles for the idea 1 metre per second equals 3.28 feet per second (1 m/s = 3.28 ft/s).

The (mouth) energy (E) has been discussed earlier. You can use the following formula to calculate the energy of your rifle: E = ½ m v². Take for example a velocity of 264 m/s with a pellet of weight m = 0.959 grams.

E = ½ x 0.000959 kg x 264² m/s

E= 33.4 Joule

From the data given from suppliers, the (mouth) energy is often difficult to determine or not realistic. For example, velocities are determined with extremely light bullets, making them very high. When suppliers specify in specific Joules, this is often a good target number rather than a specific quantity. This is because the energy of a rifle depends on the type of pellet used. It can change as a different weight of pellet is used. Variation between velocities and energy are always there even with rifles of the same make and type.

Chronograph

The easiest, fastest and most precise way to measure the speed of your rifle is with a chronometer. The cheapest models are offered from €68, such as the Acetech AC5000. Nowadays, there are also Chrono Apps available such as the "Chrono Connect Mobile". This App measures the speed of your rifle by using your phone's microphone to record the sound of the shot and its impact on the target. The App measures the time it takes for the bullet to reach the target and calculates the speed of the rifle based on this. To get the cleanest possible result, it is important that you correctly enter the distance between the end of your barrel and the target, the weight of the bullet, and the BC value into the programme. It is also important that the target being shot at is made of a material that gives a loud sound the moment you hit it.

Weights and Calibre

The weight and calibre of a bullet can be found on the can they are in. If not, the weight can often be found on the website of the relevant brand.

Form factor and BC value (G1 to G7, GS and GS)

The BC value determines the aerodynamic value of an object. This is because every object is subject to resistance when moving through the air. This resistance is expressed as the amount of force (F) that friction exerts on the object during its movement. The coefficient of resistance (Cw) depends, among other things, on the shape of an object and the structure of its surface. A ballistic coefficient does not express the amount of resistance that an object experiences, but rather its penetrating power. This means that with high air resistance, a low BC value results. The BC value of a pellet can generally be obtained from the suppliers or between pellet suppliers. A list is available at http://www.chronoconnect.com/pellet-list.html where many BC values and weights are already listed.

The Form Factor is a kind of filter added to the BC value. A standard G1 form factor is most common for an average pellet. As you can clearly see in the picture that a G7 represents a different shape. This bullet behaves differently during its trajectory. For bullets with a diabolo shape, a GA shape factor has been developed. Should this not be available in the software you use, you can also apply G1.

Scope and mounting height

You can measure the height of the scope relative to the barrel. You can do this by measuring the diameter of your scope (A), the diameter of your barrel (C) and the distance between the barrel and the scope (B). (See image)

The height of your viewer is then:

Height = ½ A + B + ½ C

The example is an AGS 3-9x40 AO Cobalt Mildot where the height is 3.75 cm.

Lasers

Everyone is familiar with the phenomenon of a laser on a weapon (we all watch films). Lasers are cheap and look cool on an air rifle. In addition, of course, they are very easy to use.

With lasers, you can easily test your parallax. If you set the laser at a fixed distance in a place where the laser in the scope is clearly visible, when you aim at the target that is at a different distance you can easily see to what extent there is a parallax deviation. You can test this by moving back and forth with your eye in front of the eyepiece; if the laser moves with it, the parallax is not properly adjusted.

You can also use a laser to correct the aiming point if it is outside the point blank. If we take our example rifle, the point blank is within 12.1 and 33.2 metres approximately.

If you want to shoot even more precisely with, say, a killzone of 0.5 (The previous calculations used a killzone of 1 cm). The OZR moves to 17 metres which makes the point blank a lot shorter. The point blank at this point is 14.7 to 29.6 metres. At this distance, the hit point of the pellet is no more than 2.5mm from the aiming point. If you want to hit something closer than 14.7 metres you will have to correct slightly this you can do with your laser.

When you mount a laser on your rifle you can create a second point blank. As shown in the image below. The red line (diagonal) is the line of the laser beam that starts 0.5 cm above the barrel and is zeroed at 13 metres. From 5 metres, the line runs until it crosses the red line of the reticle within 0.25 metres of the bullet trajectory. When aiming at short distances, your laser is well within the 0.5 cm killzone.

Use a 45-degree mount to mount the laser so that it does not sit in front of the scope. The optimum height for a laser is 0.5 cm and you can achieve this height when you mount it as close to the barrel as possible.

You pretty much only use the laser as a reference for correcting your aiming point. Therefore, it doesn't matter if the laser is at an angle to your barrel. You will always keep aiming at the target with the cross of your scope. You use the laser for correction and by turning it on very briefly the moment you aim at the target.

The tip of the laser is visible in your scope. If the dot stays below the horizontal line of the cross, this is the indication of the height of the bullet's point of impact. You can see as shown in the image that the laser lands two points below the cross. You can memorise this correction after which you turn off the laser again. Then aim at the target at the point of the second dash below the cross.

If the laser rises above the crosshair at more than 15 metres, the crosshair is your target point. You are then within the point blank of your scope which goes up to 29.6 metres. Via this route, you can shoot within a killzone of 0.5 cm with little effort within a distance of 5 to 29.6 metres. As has been indicated, a laser in this way can contribute a lot to shooting cleanly with an air rifle.