Why is it Called a Recoilless Rifle Instead of a Recoilless Rocket Launcher?

The terminology used in military weapons can sometimes be confusing, especially when discussing recoilless rifles and rocket launchers. This article aims to clarify why such weapons are referred to as 'recoilless rifles' rather than 'recoilless rocket launchers.'

Understanding Rockets and Cannons

In order to fully comprehend the distinction, it is essential to first understand the fundamental concepts of a cannon or gun projectile and a rocket. At their core, both are projectiles, as they are projected or forced forward into motion. Whether it is a cannon, a rocket, a rock, or an arrow, these objects are all propelled through some form of thrust.

A gun-fired projectile receives its thrust and forward momentum from a propellant that remains within the firing weapon. Conversely, a rocket achieves thrust and momentum from its propellant, even after it leaves the launch vehicle. This continued thrust in rockets is achieved by the propellant remaining within the rocket itself and continuing to provide propulsion during flight.

Overlap in Configuration

Despite the distinctions, there is some overlap in the design and configuration of certain weapons. For instance, modern tanks like the Abrams are equipped with a 120 mm gun that fires projectiles where the propellant remains in the gun barrel. However, the bore of the gun is not rifled, and the projectile is stabilized by fins rather than rifling.

The discussion also includes the Copperhead guided projectile which, although it does not contain propellant in flight, is capable of being steered towards its target. This projectile demonstrates the grey area between traditional cannon and rocket weaponry.

Missiles: Evolutionary Weaponry

Missiles, such as the multi-purpose 162 mm Shillelagh missile used by the U.S. military, provide another layer of complexity. Designed to be fired from a gun, the Shillelagh missile was launched from the gun mounted on the Sheridan armored reconnaissance vehicle. These missiles combine the accuracy of guided systems with the speed and range of rockets.

Missiles have become increasingly sophisticated and capable of being launched from a wide range of platforms. They offer a versatile and effective alternative to traditional artillery systems.

Recoilless Rifles: The Core Subject

The key to understanding why a weapon is called a 'recoilless rifle' rather than a 'recoilless rocket launcher' lies in the nature of the propellant's role in the weapon. A rocket, by definition, is a projectile propelled by a self-contained propellant. It can continue to accelerate the projectile even after it leaves the launcher. In contrast, a recoilless rifle employs a different mechanism.

A recoilless rifle does not contain its own propellant in the projectile. Instead, it utilizes a charged shell casing that remains within the gun. The propellant charge within this casing provides the necessary propulsion. Once the projectile exits the barrel, it no longer accelerates. The entire concept of being 'recoilless' stems from the fact that the pressure from the burned propellant is vented out the back of the gun, which counteracts the recoil.

Examples and Practical Applications

To illustrate, consider the Swedish Carl Gustav 84 mm recoilless rifle. Like a standard rifle, it provides the user with complete recoil negation. On the other hand, the AT-4, also a Swedish-built weapon, is a 84 mm missile. The AT-4 is used in a shoulder-fired configuration but operates by different principles, combining the velocity and propellant of a rocket with the accuracy of a missile system.

These examples highlight the precise distinctions between a 'recoilless rifle' and a 'recoilless rocket launcher,' underscoring the importance of understanding the underlying mechanics of these military devices.

Conclusion

The terminology around recoilless rifles and rocket launchers may seem convoluted, but by understanding the fundamental differences in their propulsion systems, it becomes clear why one is referred to as a 'recoilless rifle' rather than a 'recoilless rocket launcher.' The choice of terminology reflects the specific design and function of each weapon, ensuring that military personnel and enthusiasts can accurately identify and utilize these powerful tools of modern warfare.