Published by Pellpax | Airgun Advice | 10 min read
If you’re new to airgunning or thinking about trying a different calibre, it can be confusing to know where to start. With so many options — from .177 to .30 calibre and beyond — which one is right for your shooting style?
In this guide, we’ll break down the key differences between the most popular UK airgun calibres, focusing on sub-12 ft/lb air rifles (no licence required), while also touching on higher-powered FAC airguns where relevant.
Whether you’re into pest control, plinking, or competitive target shooting, here’s what you need to know.
What Does “Calibre” Mean in Airguns?
In simple terms, calibre refers to the diameter of the pellet your airgun fires. It’s usually measured in inches, but often shown with a metric equivalent too (e.g. .177 = 4.5mm).
Different calibres behave differently in terms of:
- Trajectory (how flat the pellet flies)
- Velocity
- Energy
- Wind resistance
- Stopping power
Understanding these traits is key to choosing the right tool for the job — especially within the 12 ft/lb power limit for UK air rifles that don’t require a Firearm Certificate (FAC).
.177 Calibre (4.5mm) – Fast and Flat
Ideal for: Target shooting, HFT/FT, plinking, light pest control
Typical pellet weight: 7–10 grains
.177 is the most popular airgun calibre in the UK — and for good reason. At sub-12 ft/lb, it delivers high velocity and a very flat trajectory, making it perfect for shooting over varied distances with minimal adjustment.
It’s the standard choice for:
- Field Target (FT) and Hunter Field Target (HFT)
- Back garden plinking
- Pest control on small quarry (e.g. pigeons, rats)
Pros:
- Flattest trajectory = easier range estimation
- Lower recoil and air usage
- Wide pellet availability and choice
Cons:
- Lower terminal energy
- More affected by wind drift
- Can over-penetrate on close-range pests
Tip: If you’re new to airgunning, .177 is a great place to start — especially if precision is your priority.
.22 Calibre (5.5mm) – Hard-Hitting Classic
Ideal for: Hunting, pest control, all-round use
Typical pellet weight: 14–18 grains
.22 is the traditional hunter’s calibre — delivering more weight and stopping power on impact. While the trajectory is more curved than .177, it hits harder, making it a great choice for:
- Rabbits and squirrels
- Close- to mid-range pest control
- Garden shooting (within your backstop)
Pros:
- Excellent stopping power at sub-12 ft/lb
- Better resistance to wind than .177
- Less risk of over-penetration
Cons:
- Requires more holdover at distance
- Slower velocity can make rangefinding trickier
Tip: Practice at different ranges so you’re confident compensating for pellet drop.
.20 Calibre (5.0mm) – The Best of Both?
Ideal for: Versatile shooters wanting a balance
Typical pellet weight: 11–14 grains
.20 sits neatly between .177 and .22, aiming to offer the trajectory of a .177 with the impact of a .22. While not as widely used in the UK, it’s a favourite among enthusiasts looking for versatility.
It’s a strong performer in both target shooting and pest control, provided you can source quality pellets.
Pros:
- Balanced flight and energy
- Great all-rounder
- Reduced wind drift compared to .177
Cons:
- Limited pellet choice
- Fewer rifles available in this calibre
Tip: If you find a gun that groups well with .20 pellets, it can be a real gem — just stock up when you find good ammo.
.25 Calibre (6.35mm) – Big Impact, Short Range
Ideal for: Close-range pest control, FAC rifles
Typical pellet weight (sub-12): 19–27 grains
At sub-12 ft/lb, .25 calibre is a niche choice. The pellets are heavy and slow, which means a very arched trajectory and limited range — usually no more than 25–30 yards. However, the knockdown power at short range is excellent.
In high-power (FAC) air rifles, .25 comes into its own with devastating energy.
Pros:
- Heavy impact, even at low power
- Ideal for barn pest control (rats, pigeons)
- Fun for reactive targets
Cons:
- Very loopy trajectory
- Poor accuracy at distance
- High pellet cost
Tip: Only consider .25 for sub-12 guns if your shooting is exclusively at close range.
.30 Calibre (7.62mm) & Beyond – FAC Only
Ideal for: FAC hunting, specialist shooting
Typical pellet weight: 44–50+ grains
Power required: 50–100+ ft/lb
.30 and larger calibres aren’t viable for sub-12 setups. The pellets are simply too heavy to fly effectively at such low power. However, in FAC-rated rifles, these big bores are capable of taking out larger quarry at range with tremendous energy.
Expect serious noise, recoil, and air usage — but also serious impact.
Pros (FAC only):
- Massive stopping power
- Excellent wind-bucking ability
- Great for larger quarry (where legal)
Cons:
- Requires Firearm Certificate
- Very expensive ammo
- Not legal for general airgun use
Tip: If you’re considering .30, you’ll need an FAC and a good reason — this calibre is serious business.
Calibre Comparison Chart
| Calibre | Trajectory (Sub-12) | Energy on Impact | Wind Resistance | Use Case |
|---|---|---|---|---|
| .177 | Flattest | Light | Poor | Target, plinking, light pests |
| .20 | Balanced | Moderate | Good | All-round use |
| .22 | Curved | Strong | Better | Hunting/pest control |
| .25 | Very curved | Strong (close) | Excellent | Close-range only |
| .30+ | Not suitable | Massive (FAC) | Excellent | FAC hunting |
Calibre vs Power: Making the Most of Sub-12 ft/lb
When you’re working within the UK’s legal limit of 12 ft/lb, calibre choice really matters. Since energy is capped, you’re always trading off between speed (trajectory) and weight (impact).
- Smaller calibres = faster, flatter shooting, less energy
- Larger calibres = slower, more powerful hits, but loopy flight paths
Ultimately, it comes down to your shooting style and what you’re shooting at.
Final Thoughts: Which Calibre Should You Choose?
There’s no one-size-fits-all answer — but here’s a quick recap:
- Go for .177 if you’re focused on accuracy, targets, or longer ranges
- Choose .22 if you want more stopping power for pest control
- Try .20 if you want a bit of both (and can find the pellets)
- Use .25 only if your shots are always close-range
- Consider .30+ only with an FAC and specific hunting needs
Need Help Choosing?
Here at Pellpax, our team of airgun experts are always happy to help you find the right setup — whether you’re new to the sport or looking to upgrade your gear. Drop us a message, call our team, or check out our full range of air rifles and ammunition online.