[News Terms] '155mm Drag-Reduced High-Explosive Shell' That Can't Last a Month in War

The '155mm Drag-Reduced High Explosive Base Bleed (K307 HE-BB) shell' is a projectile designed for 155mm howitzers. It features a separate propulsion device attached to the shell to reduce drag and extend its range. It is the main ammunition for the Korean Army's primary artillery system, the 'K9 Self-Propelled Howitzer,' which boasts top-tier performance worldwide.

Conventional shells have an aerodynamic front that reduces air resistance after firing, but the base (bottom) of the shell creates a vacuum that causes air to swirl, generating drag (a pulling force). The 'K307 HE-BB shell,' developed domestically in 1999, is equipped with a drag reduction device called a Base Bleed and is optimally shaped for aerodynamics, allowing it to achieve a maximum range exceeding 40 km.

The K9 self-propelled howitzer is firing a '155mm drag-reduced high-explosive shell (K307 HE-BB shell).'
[Photo by Agency for Defense Development (ADD)]

Base Bleed (BB) is not an auxiliary propulsion system like a rocket motor. It is simply a gas generator attached to the base of the shell. After firing, the gas emitted from this device does not provide direct thrust but eliminates the vacuum at the shell's base during high-speed flight, thereby reducing drag and enabling the shell to travel farther.

Subsequently, our military also developed the 'K315 Extended Range Projectile,' which can reach a maximum range of 60 km, but the mainstay remains the 'K307 HE-BB shell.'

It has been revealed that the military's artillery units have a critically insufficient supply of shells for wartime use. According to the Joint Strategic Operational Plan (JSOP) on the 27th, only 63% of the shells required for a 30-day war are secured for the K307 HE-BB shell, and if the conflict extends to 45 days, the stockpile drops to 54%. For the Marine Corps' 155mm high-explosive shells, only 21.3% of the necessary shells for a 30-day wartime scenario are available.

However, it has been confirmed that 155mm shells were not even included in next year's budget proposal. The 155mm shells are a highly anticipated item for defense exports, especially given the strong interest from the Middle East region. A military official stated, "We plan to make efforts to procure reserve ammunition early according to the required quantities by military branch and ammunition type."