The ships were laid down in 1974, 1978, 1983, and 1986. Those intervals gave designers time to incorporate changing systems and lessons between hulls, so each completed ship was close to its own variant. Differences in guns, point-defense missiles, and S-300-family installations mean that a shared project number can conceal meaningful equipment changes.
Notable Point · 30:29-31:24
Why each Kirov became nearly an individual design
Long gaps between keel layings allowed technology and fittings to evolve enough that the four ships differed more than a uniform class label suggests.