I am not sure that you mean by "actual combat conditions", but Russia quite regularly tests its ICBMs by launching them to the Kura test range [0] in Kamchatka. Tests usually have distance of 5-6 thousand kilometers and often include tests of MIRVs [1] with mass-equivalents of nuclear warheads.

[0]: https://en.wikipedia.org/wiki/Kura_Missile_Test_Range

[1]: https://en.wikipedia.org/wiki/Multiple_independently_targeta...