The secret Polish rifle that fooled two superpowers

Wars & Conflicts · Published 16 October 2026 Swipe more like this →

In short: Hidden in crates marked as 'optical equipment,' the wz. 35 anti-tank rifle was a masterpiece of deception. Neither German nor Soviet intelligence knew the Polish Army possessed this high-velocity weapon, which used a unique physics-based trick to defeat armor without a single armor-piercing core.

Designed by Józef Maros．szek and officially ordered in 1935, the wz. 35 was a top-secret project of the Polish Army. To maintain total surprise, the rifles were stored in sealed wooden crates labeled as 'surveillance equipment' or 'optical equipment,' with the codename 'Uruguay' used to suggest the weapons were destined for export. This secrecy was so effective that even during the 1939 Polish Campaign, the true scale of the Polish anti-tank capability remained unknown to enemy intelligence.

The rifle's lethality relied on kinetic energy rather than hard-core penetrators. Using a massive 7.92×107 DS cartridge, the weapon achieved a muzzle velocity of 1,275 m/s. Instead of punching through armor, the lead-core bullet was designed to flatten upon impact. This transferred immense energy to the steel, causing 'spalling'—where fragments of the armor plate itself are ejected into the tank's interior at high speeds, potentially killing the crew or damaging vital engines.

While the rifle was effective against contemporary German tanks like the Panzer III and IV, its specialized design had limitations. Because the bullet lacked an armor-piercing core, it could not be easily modified with incendiary or gas components. Despite the high-velocity impact, the weapon's barrel life was initially quite low, requiring replacement after only 30 shots, though later prototypes improved this to approximately 300 rounds. After the fall of Poland, many of these captured rifles were pressed into service by the German and Italian armies.

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