Leonardo TM 197B Light Turreted Gun System

Image: An A129 in flight, with personnel riding on the landing gear. By Aldo Bidini – Gallery page https://www.jetphotos.com/photo/7122665Photo https://cdn.jetphotos.com/full/1/94469_1306170545.jpg, GFDL 1.2, (Wikipedia)

The TM 197B is a specialized heliborne light turreted gun system developed by OTO Melara (now a division of Leonardo S.p.A.) to provide high-performance offensive and defensive capabilities to attack and multi-role helicopters. It was primarily designed to integrate the General Dynamics M197 20mm Gatling gun, a lighter, three-barrel version of the famous M61 Vulcan, onto the nose of the A129 Mangusta series.

The development of the TM 197B arose from the need to replace fixed 12.7 mm machine gun pods with a more versatile, high-velocity weapon capable of engaging both ground targets and low-flying aerial threats. Since its introduction, the system has seen extensive service with the Italian Army and international operators of the T129, proving its effectiveness in anti-insurgency and close-air-support roles across various global conflicts.

See the BROCHURE_2016_TM 197B

History

The TM 197B was a product of Italian engineering excellence at OTO Melara in Brescia. It was specifically optimized for the A-129 Mangusta, Italy’s first dedicated attack helicopter. Before the TM 197B, the Mangusta relied on machine gun pods that lacked the “punch” needed for modern armored warfare.

By integrating the American M197 cannon into an Italian-designed turret, Leonardo created a system that was both lethal and highly maneuverable. The turret’s ability to operate at speeds up to 140 knots ensured that the A129 remained a threat even during high-speed low-altitude ingress. Today, the TM 197B remains a staple of the A129CBT and the newer AH-129D, as well as the Turkish T129 ATAK, serving as a testament to its reliable and versatile design.

Vehicles Equipped with this Weapon

In-game, the TM 197B serves as the primary nose-mounted armament for the following Italian and Turkish attack helicopters:

• T129 (Turkey/Italy)

• A129CBT (Italy)

• AH-129D (Italy)

General Information

The TM 197B is celebrated for its low profile and reduced weight, coming in at approximately 138 kg (without ammunition). This makes it ideal for light attack helicopters where weight distribution is critical. Its three-barrel design allows for a sustained rate of fire without the extreme heat issues of single-barrel cannons, though it is intentionally capped at 750 rounds per minute to balance recoil forces and ammunition conservation.

Technical Characteristics

Feature	Specification
Caliber	20 mm
Rate of Fire	750 rds/min
Ammunition Capacity	Up to 500 rounds
Elevation Range	+20° to -50°
Azimuth Range	±100°
Turret Speed	80°/sec (Acquisition)
Recoil Force	2500N

Available Ammunition

The 20×102 mm ammunition used by the M197 within the TM 197B turret provides a versatile toolset for various engagement types. Common belt configurations typically include:

• HEI (High-Explosive Incendiary): Optimized for soft targets and thin-skinned vehicles. The incendiary effect is particularly useful for igniting fuel tanks or damaging aircraft components.

• AP-I (Armor-Piercing Incendiary): Designed to penetrate light armor (APCs, IFVs) while delivering post-penetration fire damage.

• Target Practice (TP): Standard rounds used for ranging or low-stakes engagements.

In-game, “Air Targets” belts generally prioritize HEI for maximum damage against other helicopters, while “Ground Targets” belts emphasize AP-I to defeat light armor from a standoff distance.

Comparison with Analogues

The TM 197B / M197 combination sits in a “middle ground” of helicopter armament:

• vs. M230 Chain Gun (30 mm): The M230 (found on the Apache) has a higher explosive yield per shell but lower muzzle velocity and a slower rate of fire. The TM 197B is much more effective in air-to-air dogfights due to its higher shell speed and flatter trajectory.

• vs. GIAT M621 (20 mm): The French M621 is a single-barreled cannon with a similar caliber but a lower fire rate. The TM 197B’s three-barrel rotary design generally offers better heat management for longer bursts.

• vs. Yak-B (12.7 mm): While the Yak-B has a terrifying fire rate, it lacks the armor-piercing and explosive capabilities of the 20 mm shells fired by the TM 197B.

Usage in Battles

In combat, the TM 197B is most effective when used in conjunction with a Helmet and Display Sight System (HMD). This allows the gunner to simply look at a target—whether a ground-based SAM system or an encroaching enemy scout helicopter and the turret will track their head movements at a rapid 80°/sec.

Tactical Considerations:

• Anti-Helicopter: Use the high muzzle velocity to “snipe” enemy pilots or tail rotors from 1.5–2 km away. The high accuracy allows for precision strikes that larger 30 mm cannons might struggle with due to their “loopy” trajectory.

• Ground Support: Focus on light targets. While the 20 mm AP-I can penetrate the roof or rear armor of many MBTs, it is best utilized for clearing out SPAAs and lightly armored IFVs.

• Ammunition Management: With a 500-round capacity and 750 RPM fire rate, the gunner can afford longer bursts than 30 mm users, but trigger discipline is still required for sustained sorties.

Pros and Cons

Pros:

• High Velocity: Excellent for long-range accuracy and air-to-air engagements.

• Wide Traverse: ±100° azimuth allows for firing while performing aggressive defensive maneuvers.

• Lightweight: Minimally impacts the flight performance of the A129/T129 platforms.

• Safety Features: Automatic locking into a forward position during power failure prevents the gun from becoming a hazard during emergencies.

Cons:

• Lower Punch: Lacks the raw anti-tank capability of 30 mm systems like the M230 or Shipunov 2A42.

• Capped Fire Rate: 750 RPM is slower than many other Gatling-style systems (like the 6,000 RPM M61 Vulcan).

• Limited against MBTs: Requires specific angles (top or rear) to effectively damage Main Battle Tanks.

References

Bibliography

Technical Manuals and Corporate Documents

• Leonardo S.p.A. TM 197B: Heliborne Light Turreted Gun System. Brescia: Electronics Division – Defence Business Area, 2023. Technical Datasheet.
• OTO Melara. TM 197B Technical Manual: S.N. 20 – SSMD 0075214. Brescia: Brescia Unit Documentation, August 20, 2013.

Journal and News Articles

• EDR Online. “Leonardo’s Roadmap for Medium Calibre Guns: From X-Gun to Gatling 20.” European Defence Review, May 15, 2024. https://www.edrmagazine.eu.
• Janes. “Airborne Weapons: Leonardo TM 197B Turret Integration on AW129/T129 Platforms.” Jane’s Infantry Weapons & Aircraft Armament, 2022.

Websites and Online Databases:

• Army Technology. “A129 Mangusta Anti-Tank Helicopter: Weapon Systems and Turret Capability.” Accessed December 26, 2025. https://www.army-technology.com.
• General Dynamics Ordnance and Tactical Systems. “M197 20mm Gatling Gun.” Accessed December 26, 2025. https://www.gd-ots.com.
• War Thunder Wiki. “TM 197B (20 mm).” Accessed December 26, 2025. https://wiki.warthunder.com.
• Leonardo S.p.A., TM 197B: Heliborne Light Turreted Gun System (Brescia: Electronics Division, 2023)
• OTO Melara, TM 197B Technical Manual: S.N. 20 – SSMD 0075214 (Brescia: Brescia Unit, 2013).
• EDR On-Line, “Leonardo’s Roadmap for Medium Calibre Guns,” European Defence Review, May 15, 2024, https://www.edrmagazine.eu.

Categories: Turrets | Aircraft weapons | Aircraft weapons in production and in development by the European defence industry

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