In my previous article, I briefly overviewed the Soviet 6mm program.This program was built upon a series of studies and a research and development initiative focused on sub-caliber fin-stabilized discarding sabot (FSDS) flechette ammunition, which took place from 1960 to 1981.The motivation behind this research largely stemmed from the US Special Purpose Individual Weapon (SPIW) program, which ran from the 1950s to the 1970s.In the mid-1960s, engineers at NII-61, now known as TsNIITochMash, developed sub-caliber FSDS ammunition.