I guess I am getting old because I do not remember who told me, but their experiences were such that they acted the same as Berger's.
I do know I would be willing to try them myself-I haven't done that yet though.
I know this is hearsay, but it is what I remember.
Boyd Heaton used them to kill some deer at long range. He was banned for a while from the forum for being muleheaded and ornery but mostly he is a nice guy who knows a lot of stuff so I posted his video for him. IIRC they were 30 cal 210's from a custom 300 RUM.
Len has since unbanned him, but Boyd spends all his money nowadays wrecking jeeps.