It would be fun to design experiments to see just what's going on if someone would cough up a couple hundred grand to equip a lab. Don't think it'll happen since SEE doesn't come into play with reasonable loads. As I read it Kikkonen got into it because Europeans wanted subsonic loads for .308 WCF and the like to use with their silencers, and curiosity over European WWII gallery loads. I experimented with very light loads (with unjacketed bullets and the fastest powder I could get) out of curiosity. But it was pretty much pointless with .22 rimfire standard, subsonic and CB caps available.
