No, it's true ....
Salyut 3 was launched on June 25, 1974. It was another Almaz military space station, this one launched successfully. It tested a wide variety of reconnaisance sensors, returning a canister of film for analysis. On January 24 1975 trials of the on-board 23mm Nudelmann aircraft cannon (other sources say it was a Nudelmann NR-30 30mm gun) were conducted with positive results at ranges from 3000 m to 500 m. Cosmonauts have confirmed that a target satellite was destroyed in the test. The next day, the station was ordered to deorbit. Only one of the three intended crews successfully boarded and manned the sation, but Salyut 3 was an overall success.