A version launched from submarine torpedo tubes, the S-10 Granat (SS-N-21 'Sampson'; GRAU: 3K10), has apparently been converted to carry conventional warheads and continues in service to this day.

The RK-55 is very similar to the air-launched Kh-55 (AS-15 'Kent') but the Kh-55 has a drop-down turbofan engine and was designed by MKB Raduga.

[4] Both have formed the basis of post-Cold-War missiles, in particular the 3M-54 Kalibr which has a supersonic approach phase.

They were probably nuclear-tipped S-10s during the Cold War, and then converted to use conventional warheads [7] after the START I treaty restricted sub-launched nuclear cruise missiles.

It has been suggested that S-10's could in future be fitted to converted Delta-class submarines, or to surface ships, but these have not been confirmed.