There are a lot of different pellets now on the market and can be confusing which to use especially for a beginner. We have put this guide together on the different types of pellet so you can make an informed choice on what to buy.
They come in different materials, different calibres, different weights and the different types of pellet. Even by standard calibre’s, there is a variation in actual size in 0.1 mm increments.
Wadcutter
Wadcutter pellets are arguably the most common type of airgun pellet available. They are the basic “pellet” shape, which offers a number of benefits. Wadcutter pellets are suited to close-range targets. Their shape and profile give them good aerodynamic properties, however, the flat face also gives a good impact point which leaves large holes in targets. They are often used for competition shooting because the flat surface makes a larger hole in the target.
Hollow Point Pellets
Hollow point pellets are very similar to domed pellets, but as their name suggests, they have a hollow on the tip. This is a small concave area right on the end. The hollow point has some effect on aerodynamics but encourages the pellet to flatten and fragment on impact with the target. This transfers more energy into the target than penetrating through it.
As mentioned, this design does effect accuracy and range. This pellet is generally only recommended for shorter distance hunting where accuracy is less affected. The pellet is designed to open out more on impact to ensure that you stop your prey.
There are also variations on the hollow point, or you could call them hybrid hollow points. Some have a round finish at the hollow point, others have a distinctive edge, there are other hollow points that also have a spike protruding out from the hollow itself.
Pointed
Pointed pellets have a pointed tip. This point makes them much better at cutting through material than other types. The ability to cut through things allows them to cut through the air better, giving them the benefit of 
better accuracy and range. It also allows them to cut through material better, this makes them the ideal longer range hunting pellet.
Diabolo Pellets
A mix between the flat and the pointed, also referred to as a domed pellet. With a solid head, wide skirt, and narrow waist. The rim of the skirt engages snugly with the rifled bore. Thus creating a strong spin for a flat trajectory. The pellet’s head is slightly narrower than the skirt, so there’s less friction between the head and the gun’s bore. This is designed to give maximum accuracy to the diablo pellets.
Slugs / Solid
Solid/ airgun slugs are more of a bullet design than the rest. They have the sole function of being as heavy as possible. A heavier pellet maintains its momentum better than a lighter pellet. This means that it has a much stronger impact down range. Whilst the pellet may leave the barrel at a lower FPS (feet per second), it will be less affected by air resistance and less likely to deviate due to wind.
However, Their aerodynamic shape results in a better ballistic coefficient than that of a conventional pellet, potentially giving it a greater range. It is also worth noting that most of the slugs are hollow point as well to create maximum damage. Which is better ? slugs vs pellets.
Hybrid Pellets
Pointed Hunting Pellets
These are designed to stop the prey completely, they all have an extra piece on the pellet usually made from a different material. The base of the pellet is still made in usually lead but the tip can be brass or stainless 
steel. They are made from harder material so it does not malforme on impact and thus penetrates further.
Pellets By Caliber
.30 Pellets
Quite rare to see these. Used mainly by professional vermin exterminators due to the size and weight of these beasts. They can weigh over 3g, and the largest comes in at 4,3 grams.
.25 Pellets
Again mainly used by professional hunters because of the stopping power. A little more common to see the .25 hunting pellets, but they are not designed for your average air gunner.
.22 Pellets
Probably the most common calibre of air rifle pellet. Designed for everyday air rifles, for hunting, target shooting. Very rare to see a pistol of this calibre.
.20 Pellets
Designed for everyday air rifles, for hunting, and target shooting, but it is not as popular as the .22
.177 Pellets
A very popular choice calibre of pellet used both in air pistols and air rifles. Much a much lighter pellet that should travel further and with a straighter trajectory than the heaver pellets.
Copper Pellets
Most of these are made from lead and then become copper coated pellets. They make the pellet harder with improves accuracy and penetration, also they are much cleaner to handle. Read more about the copper pellet.
Lead Free Pellets
With people focusing more on the environment the lead free pellet is becoming a more popular choice. The lead gets left around the countryside and is toxic to our wildlife. There are a few different approaches to creating lead free airgun pellets, some are made from special tin alloy. Others have plastic skirts and have solid steel in the middle, the Prometheus pellets specialise in this type of lead free pellet. A little more expensive option is to go for the gold-plated pellets, the raptor gamo real gold pellets.
BB’S
Not exactly an air gun pellet but a ball of steel that is fired from airguns. They also make a plastic version that is used in Airsoft guns.