Which Caliber Is Better: 4.5 mm or 5.5 mm? A Complete Guide

Which Caliber is Better: 4.5 mm or 5.5 mm?

This question comes up whenever someone decides to buy their first air rifle or considers switching models. The choice of caliber affects not only shooting comfort but also accuracy, effectiveness, and operating costs. In practice, both calibers have their strengths and weaknesses. Instead of looking for a single winner, it’s better to understand the differences and choose based on your needs.

.177 vs. .22 – How to Read the Markings?

Calibers are typically listed in millimeters or inches. The 4.5 mm corresponds to .177, and 5.5 mm corresponds to .22. These are the two most popular pellet sizes worldwide. You’ll find them in both spring-powered and PCP air rifles. The differences mainly stem from the pellet’s weight. Heavier pellets are slower but more stable and powerful.

4.5 mm Caliber – Speed and Precision

The 4.5 mm pellet is lighter, allowing it to achieve higher muzzle velocity. This results in a flatter trajectory and less drop. For distances of 10–25 meters, it’s hard to find a better choice. It’s no surprise that this caliber dominates in target shooting competitions.

At an energy limit of 17 J, the legal threshold in Poland, the 4.5 mm offers exceptional accuracy. Even small spring-powered air rifles in this caliber allow consistent hits on small targets. That’s why beginners often start with this option.

4.5 mm Spring-Powered Air Rifles

A classic choice—simple design, low maintenance costs, and a wide range of models. Perfect for learning and recreational shooting.

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4.5 mm PCP Air Rifles

In the PCP segment, the 4.5 mm caliber is synonymous with maximum precision. High velocity, stability, and adjustability make it the choice of competitive shooters.

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4.5 mm Pellets

A vast selection and affordable price. In Poland, 4.5 mm pellets are the most popular, ensuring easy access to various types—from flat-head to aerodynamic designs.

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5.5 mm Caliber – Power and Stability

The 5.5 mm pellet is heavier and thus slower. However, its greater mass translates to higher impact energy and less susceptibility to wind. This makes it the choice for those aiming to shoot beyond 30–40 meters.

At longer distances, the 5.5 mm maintains its trajectory and retains kinetic energy longer. That’s why it’s often chosen by shooters who use air rifles not just for recreation but also for hunting in countries where it’s legal.

5.5 mm Spring-Powered Air Rifles

Robust, powerful, and popular among those seeking greater impact on target. Ideal when energy matters more than just accuracy.

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5.5 mm PCP Air Rifles

PCP air rifles in 5.5 mm are for demanding users. High power, stable flight, and greater wind resistance make them ideal for longer ranges.

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5.5 mm Pellets

Though more expensive and less common than 4.5 mm, they offer a clear advantage at longer distances. Pellets weighing 1 g or more can resist wind and maintain accuracy where 4.5 mm starts to falter.

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Ballistics and Environmental Impact

Lighter pellets lose energy faster and are more affected by wind. Heavier pellets, on the other hand, maintain velocity longer and better cut through air resistance. In practice, 4.5 mm performs better up to 30 meters, while 5.5 mm gains an edge beyond 40–50 meters.

It’s also worth noting that pellet shape matters. Flat-head pellets offer the best precision at short ranges, domed pellets provide versatility, and pointed pellets excel at penetration. Both calibers offer a variety of pellet types, further expanding customization options.

Cost and Availability

4.5 mm pellets are not only cheaper but also more widely available. In Poland, nearly every shooting accessory store offers a large selection in this size. This is a key factor, especially for those planning frequent training sessions.

5.5 mm pellets are more expensive and less common, but the price gap is narrowing as 5.5 mm PCP air rifles grow in popularity. If you plan on extended shooting and want assurance of readily available ammunition, 4.5 mm may be the safer choice.

Legal Aspects

In Poland, air rifles up to 17 J do not require a permit. Both 4.5 mm and 5.5 mm calibers fall within this limit. If you’re considering a more powerful model, ensure its energy doesn’t exceed the legal threshold. Otherwise, you’ll need to register the air rifle as a pneumatic weapon and comply with the firearms and ammunition regulations.

Comparison Table

FAQ – Frequently Asked Questions

Does the choice of caliber matter for air rifles up to 17 J?

Yes. Even at the same energy level, 4.5 mm achieves higher velocity and better accuracy at short ranges, while 5.5 mm delivers greater kinetic energy at longer distances.

Which caliber is better for beginners?

For those new to shooting, 4.5 mm is recommended. It’s cheaper, easier to handle, and more forgiving during the learning process.

Is 5.5 mm always more powerful?

Not always. Power depends primarily on the air rifle’s design. However, at the same initial energy, a 5.5 mm pellet transfers more force to the target due to its greater mass.

How does wind affect performance?

5.5 mm pellets are less susceptible to crosswinds, giving them an advantage in challenging weather conditions. 4.5 mm pellets are more likely to be deflected off course.

Which caliber is better for hunting?

In countries where hunting with air rifles is legal, 5.5 mm is often preferred for its better penetration and impact energy.