Designed Specifically For F-35 Fighters, Australia Acquires APEX ‘Armor Piercing’ Ammo From Nammo

Australia has inked a major deal to arm its fleet of F-35A Lightning II jets with 25mm PGU-47/U APEX ammunition sourced from Norwegian-Finnish defense manufacturer Nammo. 

The contract, valued at AUD 22.9 million (US $14.2 million), is the first major sale of advanced ammunition, which is specifically designed for the F-35 fifth-generation fighter jet. 

The agreement was recently announced by Nordic defense firm Nammo, with confirmation provided by a spokesperson for Australia’s Department of Defence on January 15. 

The ammunition was developed through a collaboration between Nammo, the Norwegian Defence Materiel Agency (FMA), and the Norwegian Defence Research Establishment (FFI). 

The entities have dedicated nearly two decades of research, development, and testing to ensure the ammunition’s readiness for the F-35A fighter jets. 

Medium Caliber Production. Photo: Frank Holm/Nammo

Nammo said the firm “has made other sales in the past, and there are other countries testing or using the APEX ammunition.” However, it cannot disclose additional details about those programs, likely due to security reasons.

Production for Canberra is scheduled to begin this year, with deliveries expected to continue until 2027. 

The APEX rounds are designed to be used with the F-35A’s internal GAU-22/A four-barrel rotary cannon. It will provide additional firepower for the aircraft and complement its already formidable suite of weaponry.  

Australia DoD spokesperson said the APEX rounds will offer “a number of operational benefits, including the ability to be effective against a range of targets and improved warhead performance and accuracy.”

The advanced capabilities of the F-35A, including its precision-guided munitions and cutting-edge avionics, help the aircraft handle most combat scenarios without reliance on close-range weaponry. 

The aircraft is also equipped with air-to-air missiles, such as the AIM-9X Sidewinder and AIM-120 AMRAAM, as well as Joint Direct Attack Munitions (JDAM) and laser-guided bombs.

The F-35B, designed for short takeoff and vertical landing (STOVL), and the naval F-35C variant do not feature an internal cannon. However, both can be outfitted with an optional centerline gun pod armed with the GAU-22/A rotary cannon, which holds up to 220 rounds. 

Nonetheless, the F-35A is currently the backbone of Australia’s air combat fleet. In December 2024, Australia took delivery of the final batch of nine F-35A jets, completing its full fleet of 72 aircraft. 

Beyond the F-35A, Australia’s air capabilities are backed by Boeing F/A-18F Super Hornets and EA-18G Growlers.  

APEX Ammunition

The APEX ammunition offers a cutting-edge solution for modern air combat, tailored specifically for the F-35 fighter jet. This advanced projectile is engineered to target a wide range of threats, from aerial targets to soft and armored ground targets. 

The APEX round is equipped with an explosive-filled warhead that utilizes a delayed initiation mechanism, delivering a powerful combination of blast, fragmentation, and incendiary effects directly inside the target. Additionally, the projectile features a nose-mounted penetrator for improved penetration capability.

According to the manufacturer’s website, the PGU-47/U projectile weighs 222 grams and has a muzzle velocity of 970 m/s when fired from the F-35. It offers a maximum dispersion of less than 0.5 mils from a single barrel. 

In terms of penetration, it can penetrate 14 mm of steel at a 45° angle at 9,000 feet or 8 mm of rolled homogeneous armor (RHA) at the same angle and altitude. 

The tracer has a burn time of over 3 seconds, and the projectile is designed to operate within a service temperature range of -62°C to +80°C. It has been qualified for use in the F-35A. 

Exercise Lightning Ferry 2024
A Royal Australian Air Force F-35A Lightning II aircraft touches down at RAAF Base Williamtown, New South Wales (Australia DoD)

The ammunition’s design also incorporates a dual-safety fuze (FMU-171/U) to ensure safe arming at a distance from the aircraft, with a detonation delay upon target impact. 

This advanced fuze functionality is a key feature that improves the overall safety and effectiveness of the APEX in combat scenarios. 

What sets the APEX apart from other ammunition types is its combination of armor-piercing and explosive effects in a single round. The tungsten carbide penetrator provides formidable armor-piercing capabilities, while the explosive warhead ensures devastating internal damage upon impact. 

The round remains effective even when striking targets at an angle, which makes it reliable for grazing hits, unlike traditional ammunition that requires direct hits for maximum impact. 

Although specifically designed for the F-35, the APEX can also be used on platforms equipped with the M242 Bushmaster gun.