The Resurgence of the 25×137 mm Caliber in Modern Warfare
Historical Context and Evolution
During the Cold War, the 25×137 mm caliber was a dominant choice for Western infantry fighting vehicles (IFVs), effectively countering the threats posed by the armored vehicles of Warsaw Pact nations. However, advancements in armor technology led many nations to transition towards larger calibers, including the 30×173 mm and 35×228 mm, and even the 40×255 mm cased telescoped ammunition. In light of emerging threats such as flying precision munitions and loitering munitions, the 25×137 mm caliber is experiencing a revival, as exemplified by Rheinmetall’s recent introduction of its CT-025 unmanned turret at DSEI.
Resurgence of the KBA Cannon
A few months prior, discussions at Rheinmetall Italia highlighted the renaissance of the 25×137 mm caliber. Approximately three years ago, the dual belt-feed KBA cannon appeared on the brink of obsolescence due to the shift towards larger calibers in new IFV programs. The ongoing conflict in Ukraine and the proliferation of small UAVs have prompted a reconsideration of the capabilities provided by the 25 mm system. The KBA’s design, which draws parallels with the AR-15 operating mechanism, has been developed over decades, originating from the 1960s with contributions from Swiss-based Oerlikon-Bührle and an American firm. The first significant adoption of the KBA occurred in the Royal Netherlands Army, where it was integrated into the YPR-765 IFV.
Advantages and Features of the KBA Cannon
Rheinmetall emphasizes several key benefits of the KBA cannon:
- Integration and Mass: Weighing only 112 kg, the cannon allows for straightforward system integration on various platforms.
- Recoil Management: Recent versions demonstrate a capacity to mitigate 50% of recoil, enhancing operational effectiveness.
- Ammunition Flexibility: The Instant Ammunition Selection Device (IASD) facilitates rapid switching between ammunition types, adapting seamlessly to diverse mission profiles, ranging from ground engagements to countering drones and other aerial threats.
Specific to countering UAVs, the KBA cannon is paired with the MES 327 round, a 25×137 mm high-explosive projectile featuring a proximity fuse.
Operational Versatility
The KBA’s adaptable rate of fire is a notable feature. Operators can select from single-shot or rapid-fire options, achieving up to 650 rounds per minute in automatic mode, with an effective combat range extending to 2,700 meters. The cannon has been qualified for a variety of ammunition types, including:
- Full-Caliber: HEI, HEI-T, TP, TP-T, and FAP.
- Sub-Caliber: FAPDS-T, APFSDS-T, and TPDS-T.
Performance specifications indicate that a 25 mm APFSDS round can penetrate approximately 90 mm of rolled homogeneous armor, compared to a 30 mm round capable of penetrating 130 mm.
Introduction of the CT-025 Unmanned Modular Turret
At DSEI, Rheinmetall unveiled the CT-025, an advanced unmanned modular turret armed with the KBA cannon. This dual-role turret is positioned as a pivotal element in reinvigorating the 25 mm caliber’s relevance on the global market. Key design features include:
- Enhanced Sighting Systems: The SEOSS320 sighting system is optimized for air defense, equipped with a CMOS day camera, thermal imager, and an extensive laser rangefinder.
- Reloading Efficiency: Two accessible hatches enable quick reloading of two magazines, each accommodating a minimum of 125 rounds.
The CT-025’s digital architecture is modular, allowing for seamless integration with Rheinmetall’s Battlesuite and ensuring adaptability to specific customer requirements.
System Specifications and Applications
Estimations indicate that the CT-025 turret, excluding armament and ammunition, has a mass of about 750 kg. When combined with the 112 kg KBA cannon and approximately 125 kg of ammunition (for a load of 250 rounds), the total weight is manageable for installation on light armored vehicles.
Rheinmetall’s aspirations include integrating the CT-025 turret with the upcoming Korsak reconnaissance vehicle for the German Army, which is set to progressively replace the Fennek. Despite previous plans to arm the LuWa weapon carrier with the KBA, that program has been halted.
In summary, the CT-025 and the KBA cannon represent a concerted effort to bolster Rheinmetall’s medium-caliber turret offerings, providing military forces with versatile, lightweight solutions to counteract modern asymmetric threats effectively.
Photos by Rheinmetall Italia and P. Valpolini
This overview underscores the growing interest in versatile weapon systems that can adapt to the complexities of contemporary warfare, highlighting a potential shift back to calibers once deemed less relevant.
