These were solid-fuel rockets, but I would like to know what exact rocket fuel they used, because it relates to a few of my other questions:
Edit: Forgot to post my research. So far the closest thing I found was this page from Russianspaceweb.com on the RT-1, apparently Russia's first large solid rocket. It says "These engines burned essentially same powder fuel which had propelled the famous 1930s-vintage Katyusha rockets. (177)" and down in the chart it says "Propellant Solid --- RSD-4K". I tried googling that but got nothing.