I have a rather "rotund" friend here in Australia who I let have shots with my 375 and the fat shock wave you mentioned really is a thing as we watched it travel back and forth through his body.300+ LB friend bought a 700 safari in 375H&H, bunch of us watched him shoot it for the first time one hot summer day.
When he touched off the recoil sent a fat shock wave down his body, he then turns to us and says
"Farking Brutal". We literally peed in our pants laughing.