Early in development, Steyr Mannlicher started with 12.7mm and 15mm caliber rounds, before transitioning to a 14.5mm APFSDS round. The caliber was later changed to 15.2×169mm APFSDS.
The casing is plastic with a steel base and is bottlenecked. The projectile is a fin-stabilised, 20 gram 5.56mm caliber tungsten or depleted uranium penetrator dart that sits in a 15 gram plastic sabot with an effective range of 1,000 to 2,000 meters depending upon the nature of the target.
At a range of 800 meters, the dart will penetrate 40mm of Rolled Homogeneous Armour (RHA), with considerable secondary fragmentation behind the plate. The high velocity produces an exceptionally flat trajectory. The vertex at the 1,000 meters range is only 800mm above the line of sight. The cartridge uses a long primer to give optimum ignition of the propelling charge, and a pusher plate drives the projectile up the bore.