Sarmat was not the one I saw discussed. I saw it was a variation of Topol. It has different names according to its payload. With a Nuclear payload, it could be ICBM, conventional is heavier so it travels less.
This one is named "Oreshnik" and is supposedly derived from a predecessor RS-26 "Rubezh" IRBM. You appear to be correct about range tinkering by adjusting warhead weight, which is what was demonstrated with the RS-26.
Sarmat was not the one I saw discussed. I saw it was a variation of Topol. It has different names according to its payload. With a Nuclear payload, it could be ICBM, conventional is heavier so it travels less.
This one is named "Oreshnik" and is supposedly derived from a predecessor RS-26 "Rubezh" IRBM. You appear to be correct about range tinkering by adjusting warhead weight, which is what was demonstrated with the RS-26.