Tank Weapon Systems: How Main Guns and Coaxial Arms Work

Tank weapon systems are the collection of guns, ammunition handling, and aiming equipment mounted on a main battle tank, designed to engage enemy vehicles, personnel, and fortifications. For everyday readers, the topic can seem technical, but the core ideas are straightforward.

This article describes the main parts of a tank’s armament, how crews use them, and the trade-offs designers weigh when choosing what a tank carries and how it is controlled.

Why a Tank Carries More Than One Gun

A modern main battle tank is usually armed with several weapons rather than one. Each weapon fills a different job, from destroying armored vehicles at long range to suppressing enemy infantry at close distance. Combining them lets a single crew respond to many kinds of threats without changing position.

The arrangement reflects a basic military principle: the right tool depends on the target. A large cannon is poor at hunting individual soldiers, while a machine gun is useless against thick armor. Designers therefore pair a heavy gun with lighter weapons that cost less ammunition and are easier to fire repeatedly.

Understanding this layered approach helps explain why tank armament looks the way it does. The gun is only one part of a larger system that includes ammunition storage, sights, stabilization, and crew procedures, all working together to turn a target into a result.

The Main Gun and Its Ammunition

The main gun is the largest weapon on a tank, typically a smoothbore cannon that fires fin-stabilized projectiles and, in some designs, explosive shells. Its size determines how much armor it can defeat, and modern tanks generally use one of a small number of standard calibers, chosen by each country’s doctrine.

Ammunition is stored in the hull or turret, often in an armored compartment designed to limit damage if a round is hit. Rounds are typically loaded by a human crew member or by an automatic loader, depending on the design. Careful separation, protection, and trained handling are central safety principles for all tank ammunition.

Choosing ammunition involves trade-offs. Kinetic rounds rely on speed and mass to punch through armor, while chemical energy rounds use a shaped charge. Each has strengths against different targets, and armies select the mix that matches their expected enemies and missions.

Coaxial and Secondary Machine Guns

Beyond the main gun, most tanks carry several smaller weapons, each with a specific purpose. These are commonly grouped by where they are mounted and what they are designed to engage.

• A coaxial machine gun mounted beside the main gun, aimed along the same line for quick engagement of soft targets.
• A commander’s machine gun, often on a cupola, used for defense and suppression of nearby infantry.
• A bow or hull machine gun, fixed forward and typically fired by the driver or a dedicated gunner.
• An anti-aircraft machine gun, mounted on the turret roof for use against low-flying aircraft and helicopters.
• A smoke or grenade launcher system, used to screen the tank or confuse enemy observation.

These secondary weapons give the crew flexibility without drawing on the main gun’s expensive ammunition. Their exact arrangement varies widely between tank designs and national armies, and each army’s doctrine determines how many are fitted and how they are used in practice.

Fire Control and Aiming Systems

Fire control is the set of sensors, computers, and sights that help a crew find, track, and hit a target. It typically includes a gunner’s sight, a commander’s independent sight, a laser rangefinder, and sensors that measure environmental conditions such as crosswind and temperature.

Gun stabilization keeps the barrel pointed at the target while the tank moves over rough ground. Without it, a tank would struggle to fire accurately on the move. Stabilization, combined with fire control, is one of the main reasons modern tanks can engage targets while travelling.

These systems depend heavily on electronics and training. A well-designed sight is only as good as the crew that uses it, which is why military forces invest significant time in gunnery practice and drills.

Crew Roles in Operating Weapons

A tank crew usually includes a commander, a gunner, a loader, and a driver, although the exact number depends on the design. Each member has defined responsibilities for aiming, loading, moving, and communicating, and they must coordinate quickly under pressure.

The gunner typically operates the main gun and coaxial machine gun, while the commander may direct targeting and take control of a secondary weapon. The loader handles ammunition when the tank has no automatic loader, a task that demands speed and strict attention to safety.

Doctrine and regulations set the exact procedures for each role. Armies emphasize repeated drills, because consistent teamwork is one of the most important factors in effective weapon use.

Weapon Systems Compared Across Designs

Tank weapon systems differ meaningfully between designs, reflecting national priorities and the era in which each tank was built. The comparison below highlights the main categories that analysts usually consider.

Main Gun Calibers and Their Purpose

Main guns are grouped mainly by caliber, which describes the diameter of the barrel. Larger calibers generally allow heavier projectiles and more energy, but they also add weight and require stronger turrets and more space for ammunition.

Designers balance caliber against mobility and logistics. A larger gun can defeat more armor, yet it may limit how much ammunition a tank can carry. The best choice depends on the expected threats and the wider force structure.

Exact caliber figures and performance data are set by each nation’s military and are not uniform across the world. Readers seeking precise specifications should consult official documentation rather than general summaries.

Automatic Loaders Versus Manual Loading

An automatic loader is a mechanism that moves ammunition from storage into the gun breech, reducing the number of crew members needed. Some designs use this approach to make room for a smaller crew, while others keep a human loader.

Each approach has trade-offs. Automatic loaders can speed up firing and free space, but they add mechanical complexity and can be harder to repair in the field. Manual loading relies on the crew but is simpler to maintain and can be more adaptable.

Military planners weigh these factors against crew size, maintenance capacity, and the expected operating environment.

Remote and Stabilized Weapon Stations

Some modern designs use remote weapon stations, which allow a crew member to operate a weapon from inside the protected hull using cameras and screens. This keeps the crew shielded while still allowing the weapon to be aimed and fired.

Remote systems can reduce exposure, but they depend on sensors, power, and communications that may be vulnerable to damage or interference. Designers therefore include backup modes and manual controls to keep the weapon usable when electronics fail.

Whether a tank uses a remote station or an open turret weapon is a design decision shaped by protection goals, cost, and maintenance concerns.

Limitations and Trade-offs in Tank Armament

No tank weapon system is perfect. A heavy gun improves lethality but adds weight, which affects speed, fuel use, and transportability. Designers must decide how much firepower to accept in exchange for mobility and protection, and different armies answer that question differently.

Ammunition capacity is another limit. Storing large numbers of rounds takes space and may increase the risk of catastrophic damage if the storage area is hit. Engineers therefore design protective compartments and ventilation, applying general safety principles for hazardous materials.

Electronics bring their own constraints. Advanced sights and stabilization require power, cooling, and regular maintenance. Armies must plan for these needs, because a weapon that cannot be kept working in the field offers little value.

How Doctrine Shapes Weapon Choices

Doctrine is a nation’s official guidance on how its forces fight, and it influences almost every weapon decision. It shapes which gun is fitted, how many secondary weapons are carried, and how crews are trained to use them.

A force designed for open terrain may prioritize long-range accuracy, while one operating in cities may value close-range suppression and rapid fire against infantry.

Doctrine also determines training priorities. If a military expects tanks to fight alongside infantry, its crews will practice coordinated fire with troops on foot and communication under noise and stress. If it expects armored duels, gunnery against moving targets and fast target transitions may receive more time on the range.

Because doctrine evolves, weapon systems are often upgraded over the years. Armies revisit their assumptions after observing real conflicts, large exercises, and changes in technology, and they adjust fittings and procedures to match new priorities.

Lessons From the History of Tank Armament

The history of tank weapons shows steady change. Early tanks carried relatively small guns and several machine guns, and their designers often focused on suppressing infantry. As armor thickened on both sides, guns grew larger and fire control became more sophisticated, with better sights and more reliable ways of aiming on rough ground.

Major conflicts repeatedly exposed weaknesses that prompted redesign. Crews discovered that poor sights, slow loading, or unreliable electronics could decide an engagement in seconds, and those lessons led armies to invest in better training, clearer procedures, and more dependable equipment.

These lessons remain relevant. The overall pattern is that weapon systems succeed when they match real missions, are easy to maintain in the field, and are operated by well-trained crews who understand both the equipment and the doctrine behind it.

Questions to Ask When Evaluating a Tank’s Armament

Readers who want to judge a tank’s weapons sensibly can ask a few practical questions. These help separate meaningful capability from marketing claims.

• What targets is the main gun designed to defeat, and how does its caliber relate to those targets?
• How many rounds of each ammunition type can the tank carry, and where are they stored?
• Does the fire control system support accurate firing while the tank is moving?
• What secondary weapons are fitted, and do they serve roles the main gun cannot?
• How is the system maintained, and what support does the military provide for repairs?

Answering these questions requires official data, which varies by nation and model. Clear reasoning about purpose, trade-offs, and sustainment is often more useful to the general reader than any single performance figure.

Practical Next Steps for Following Armor Developments

Readers who want to follow developments in tank armament can start with official defense publications, parliamentary or congressional reports, and reputable defense analysis organizations. These sources explain procurement decisions, testing results, and changes in doctrine in careful detail.

It also helps to compare how different armies approach the same problems. Looking at why one force chose a remote station while another kept an open turret weapon reveals the reasoning behind design decisions, which is more informative than headline specifications.

As armies continue to modernize, the core questions remain the same: what the weapon must do, how it will be controlled, and how it will be sustained. Keeping those questions in mind makes the subject far easier to understand.