My thought is, you put a bullet hole through both lungs, the animal will die, period..
As to Postman's story..there are, IMHO, so many variables there to really draw any type of conclusion that would be credible..

Were the 30-30 shooters shooting at running game?? Was the '06 shooter maybe just a better shot? Was he using a scope vs open sights? all open sights?? all scoped?? types of bullets used by both??

I used a 30-30 for a couple years after I left the farm just for nostalgia ..had no problems on the whitetail..and we are also very far north..on the Canadian line--so, also very large deer..

Stick with my story.. 22 rimfire, 30-30 or 300 Win Mag--put a legitimate hole through BOTH lungs..they die, period..

hell I killed a whitetail doe in my back yard accidently with a 22 pellet gun..