this is sort of a tutorial on how i currently make 7.62x25 brass for my CZ-52 from used .223 brass. this is the fastest way i know how to make it right now. the only problem is that to make it fast you must invest in some tools, as doing it all by hand takes a while and is a PITA.
https://www.youtube.com/watch?v=RFKOMObl6KM