6.35 mm Pellets (.25 Calibre): Weight, Energy and Accuracy for Air Rifles
6.35 mm pellets, also known internationally as .25 calibre pellets, are among the larger projectiles commonly used in air rifles. Their greater mass compared with 4.5 mm and 5.5 mm pellets allows the use of heavier projectiles that can retain energy effectively throughout their flight.
At Carbin, you can find .25 calibre / 6.35 mm pellets from specialist manufacturers such as JSB and H&N Sport, together with other recognised brands such as RWS and Gamo. Different weights, profiles and designs allow shooters to find the combination that works best with a particular air rifle.
The 6.35 mm calibre is particularly common among PCP air rifles. Pre-charged pneumatic technology is especially well suited to heavier projectiles and allows shooters to take advantage of the characteristics of the .25 calibre.
What Do 6.35 mm and .25 Calibre Mean?
The terms 6.35 mm and .25 calibre refer to essentially the same nominal projectile diameter expressed using two different measurement systems.
- 6.35 mm: the metric designation commonly used in Europe.
- .25 calibre: the imperial designation widely used in the international airgun market.
If an air rifle is marked as .25 calibre, its ammunition will commonly be sold in European markets as 6.35 mm pellets.
What Is the Difference Between 6.35 mm, 5.5 mm and 4.5 mm Pellets?
The main difference lies in the diameter and mass of the projectile. In general, 6.35 mm pellets are heavier than 5.5 mm pellets, while 5.5 mm pellets are normally heavier than 4.5 mm pellets.
These differences affect velocity, trajectory, retained energy and overall ballistic behaviour. A heavier pellet may retain energy effectively, but it also requires an air rifle capable of accelerating that projectile appropriately.
| Calibre | Nominal Diameter | General Characteristics |
|---|---|---|
| .177 | 4.5 mm | Light projectiles and generally flatter trajectories |
| .22 | 5.5 mm | A balance between projectile weight, velocity and energy retention |
| .25 | 6.35 mm | Heavier projectiles and strong energy retention |
There is no single calibre that is universally better. The right choice depends on the air rifle, its power, shooting distance and intended use.
Why Is the Weight of a 6.35 mm Pellet So Important?
There can be significant weight differences between pellets of the same 6.35 mm calibre. Pellet weight is often expressed in grains (gr) and is one of the most important factors when choosing airgun ammunition.
Two pellets of the same calibre but different weights can produce different velocities, trajectories and group sizes when fired from the same air rifle.
For this reason, choosing a pellet based only on calibre is not enough. Weight, shape, overall length and compatibility with the specific air rifle should also be considered.
6.35 mm Pellets for PCP Air Rifles
The 6.35 mm calibre is especially common among PCP air rifles. Pre-charged pneumatic systems are particularly well suited to relatively heavy projectiles and allow several shots to be fired using the compressed air stored in the rifle's reservoir.
However, two PCP air rifles in the same calibre will not necessarily achieve their best accuracy with the same pellet.
Power level, barrel characteristics, rifle setup and the exact weight and geometry of the pellet can cause one particular reference to perform exceptionally well in one rifle and differently in another.
If you are specifically looking for a platform designed to make effective use of this calibre, explore our range of PCP air rifles.
6.35 mm Pellet Shapes: Which Design Should You Choose?
In addition to weight, the geometry of the pellet affects its flight and shooting characteristics. Several different profiles are available in .25 calibre, each offering different aerodynamic characteristics.
Domed Pellets
Domed pellets have a rounded head and are one of the most popular designs when shooters are looking for good aerodynamic performance and accuracy across different distances.
Flat Head or Wadcutter Pellets
Flat head pellets, also known as Wadcutters, are traditionally associated with paper target shooting because they produce clean, clearly defined holes. Their aerodynamic behaviour differs from that of a Domed pellet, particularly as distance increases.
Pointed Pellets
Pointed pellets use a different head geometry and can behave differently depending on projectile weight, velocity and the barrel from which they are fired.
Hollow Point Pellets
Hollow Point pellets feature a cavity in the head of the projectile. As with other pellet designs, their actual behaviour depends on factors such as velocity, distance and the characteristics of the air rifle.
If you want to understand the differences between Domed, Wadcutter, Pointed, Hollow Point and other pellet profiles in greater depth, read our guide to pellet classification and pellet types.
JSB, H&N Sport, RWS or Gamo: Which 6.35 mm Pellets Should You Choose?
Leading airgun ammunition manufacturers offer a wide range of pellets in 6.35 mm / .25 calibre. JSB pellets are available in different weights and designs, while H&N Sport pellets also provide a broad selection for different air rifles and shooting disciplines.
Manufacturers such as RWS and Gamo further expand the range with different weights, profiles and projectile designs.
Rather than assuming that one brand is universally superior, it is better to find the pellet that produces the tightest groups with your particular barrel and rifle.
Why Does an Air Rifle Shoot Better with Some Pellets Than Others?
One of the most interesting characteristics of air rifles is that every combination of barrel and projectile can behave slightly differently.
Actual head diameter, weight, alloy, geometry and manufacturing tolerances can all influence group size and consistency.
For shooters looking for maximum accuracy, testing several compatible pellet references under similar conditions and comparing the resulting groups is one of the most reliable approaches.
Are 6.35 mm Pellets Suitable for Longer-Range Shooting?
6.35 mm pellets can perform very well at extended distances when matched with a suitable air rifle, partly because their greater mass compared with smaller calibres can help them retain energy during flight.
However, a larger calibre does not automatically guarantee greater long-range accuracy. Muzzle velocity, projectile weight, shape, aerodynamic behaviour, rifle consistency and environmental conditions all influence the final result.
6.35 mm Pellets and Energy
Calibre alone does not determine the energy of a projectile. Kinetic energy depends on both projectile mass and velocity.
As a result, two 6.35 mm pellets with different weights can produce different velocities and energy levels when fired from the same air rifle.
With PCP air rifles, measuring actual pellet velocity with a chronograph can help evaluate how a particular rifle and pellet combination is performing.
How to Choose the Best 6.35 mm Pellets for Your Air Rifle
Before choosing a .25 calibre pellet, several factors should be considered:
- Exact calibre: confirm that your air rifle is designed for 6.35 mm / .25 calibre.
- Weight: choose a pellet weight suited to the power and characteristics of the rifle.
- Shape: Domed, Wadcutter, Pointed and Hollow Point designs have different characteristics.
- Air rifle type: 6.35 mm is particularly common among PCP platforms.
- Magazine compatibility: in multi-shot rifles, projectile length and geometry should also be considered.
- Grouping: testing different pellet references on paper remains one of the best ways to identify the ammunition your rifle prefers.
6.35 mm Pellets and Multi-Shot Magazines
With a multi-shot PCP air rifle, calibre is not the only factor that matters. The overall length and geometry of the pellet may also be important for reliable feeding through the magazine.
Especially long pellets or projectiles with unusual profiles may have different levels of compatibility depending on the magazine design. Always check the specifications of the specific rifle and magazine system.
Diabolo Pellets or Slugs in .25 Calibre?
In .25 calibre, shooters can find both traditional Diabolo pellets and other projectile designs such as slugs.
A Diabolo pellet uses the characteristic narrow waist and flared skirt associated with traditional airgun ammunition. Slugs use a different projectile geometry and are particularly associated with certain higher-powered PCP air rifles.
Not every air rifle is equally well suited to both projectile types. Before changing from conventional pellets to slugs, check the manufacturer's recommendations and the compatibility of the barrel, magazine and feeding system.
Frequently Asked Questions About 6.35 mm Pellets
Is .25 Calibre the Same as 6.35 mm?
Yes. In the airgun world, .25 calibre and 6.35 mm are the common imperial and metric designations for essentially the same nominal projectile diameter.
What Weight 6.35 mm Pellet Should I Use?
That depends on the air rifle, its power level and the shooting characteristics you want. There is no single pellet weight that is optimal for every 6.35 mm air rifle.
Are 6.35 mm Pellets Suitable for PCP Air Rifles?
Yes. The 6.35 mm calibre is particularly common among PCP air rifles, where pre-charged pneumatic systems can work efficiently with relatively heavy projectiles.
Which 6.35 mm Pellets Are the Most Accurate?
Accuracy depends on the combination of pellet, barrel and air rifle setup. Manufacturers such as JSB, H&N Sport, RWS and Gamo offer different options, but the most reliable approach is to test several suitable pellets in your own rifle.
Is a Heavier Pellet Always More Accurate?
No. A heavier pellet changes velocity and trajectory, but does not automatically produce tighter groups. Accuracy depends on the interaction between the rifle, barrel, projectile and shooting conditions.
Can I Use Any .25 Pellet in a 6.35 mm Air Rifle?
The manufacturer's specifications should always be checked. With magazine-fed air rifles, overall projectile length and geometry must also be compatible with the feeding system.
Which 6.35 mm Pellet Shape Is Best?
There is no single design that is ideal for every use. Domed pellets are particularly popular because of their aerodynamic characteristics, while other profiles are designed for different purposes. Learn more in our guide to the different types of airgun pellets.
Are 6.35 mm Pellets Good for Longer Distances?
They can perform well at extended distances when paired with a suitable rifle, but final accuracy also depends on velocity, projectile weight and design, rifle consistency and environmental conditions.
Can I Use .25 Slugs in Any 6.35 mm PCP Air Rifle?
Not necessarily. Even though the nominal calibre is the same, compatibility depends on the barrel, projectile length, magazine and overall design of the air rifle.
Buy 6.35 mm Pellets at Carbin
At Carbin, you can find a selection of 6.35 mm (.25 calibre) pellets from specialist manufacturers such as JSB, H&N Sport, RWS and Gamo.
Compare different weights, profiles and manufacturers to find the projectile that best suits your air rifle. Explore our ranges of JSB pellets and H&N Sport pellets.
If you want to understand the differences between Domed, Wadcutter, Pointed, Hollow Point and other profiles before choosing, read our complete guide to pellet classification and pellet types.
And if you are looking for a platform designed to make effective use of heavier .25 calibre ammunition, browse our PCP air rifles.
