re: New Winchester Subsonic Super X .308

Full disclosure: I've never killed any game animal w/ a subsonic 300 Whisper/Blackout or 308 Win. Having said that, there's a handgun hunter who's written extensively about killing a large number of game animals and varmints w/ subsonic 300 Whisper loads (ballistic twin to 300 Blackout). He knows what he's talking about. He's a family practice MD who kills >500/year groundhogs and >50/year deer. On deer, he's killed deer to 200 yards w/ the 200 gr Sierra RN bullet and to 250 yards w/ the 170 gr Lehigh Defense load. I'll include a few links, but for anyone who wants to read more, just google WV Hitman and 300 Whisper. From what he says, the subsonic bullets kill from the bullet "tumbling", not from the usual expansion/shock seen in supersonic bullets.
Link 1.
Link 2.