In the early 1970s, Poland wanted to replace their 7.62x39mm Kalashnikov rifles. The Soviet Union was developing the 5.45mm AK-74, but the Poles wanted to make a more ambitious advance in small arms systems. They launched Project Lantan... The plan was to create a modular system similar in concept to the Stoner 63 โ a single universal receiver that could be fitted with different components to create variety of weapons. These could include a short carbine, infantry rifle, mag-fed light machine gun, squad automatic, or vehicular machine gun (fired by spade grips or remote solenoid).
The cartridge developed for the rifle was an indigenous 7x41mm round that was longer and more efficient than 7.62x39mm. Two prototype rifles were built... we have a chance to take a close look at number 1. Unfortunately its experimental foam/rubber stock has completely disintegrated in the past 50 years since it was built, but the rest of the rifle is intact. It features separate upper and lower receivers and a quick-change barrel and gas tube.
Once the Soviet Union found out about the project, they forced it to be cancelled. The Soviets wanted caliber commonality within the Warsaw Pact, and they also wanted to collect a license fee from Poland for the AK-74 and 5.45x39mm cartridge. In this they were only partially successful, as the Poles reverse engineered elements of the AK-74 to create their own unique Tantal rifle design instead of licensing the new Kalashnikov. But even so, the Lantan project was squashed before it could advance beyond two initial proof of concept rifles.
Ian's video [15:25] https://youtu.be/5f-nfoLqdO0?si=
https://www.forgottenweapons.com/project-lantan-poland-designs-a-modular-ak-in-7x41mm/
So the Soviets wanted to make money from licensing? Pick a lane, communists!