In .308 diameter bullets between 308, 30/06, 300 WM, PRC, Weatherby, RUM, Lapua, RUM Imp, 30/378, Warbird, etc. I have killed and seen killed hundreds of deer. With 6.5’s in CM, x47, 260, 6.5-284, PRC, 264 WM, 26 Nos, 6.5-300 Wearherby, etc. it is less, but still well over a hundred deer.
Given bullets that maximize tissue destruction, the big 30cals do create more tissue damage and hence faster incapacitation. However I would wager a healthy bet that NO ONE wants what those bullets do to normal sized deer.
On deer sized game (sub 300lbs) maximized tissue destruction is the 178gr ELD-M/Amax for readily available bullets in .308. With bigger 6.5’s max destruction is between the 140gr and 147gr ELD-M, and 130-140gr Berger VLD’s.
A 30cal normal magnum producing around 3,000fps MV or a bit more from the 178gr ELD-M will produce
permanent wound channels of 8-9” above 2,400fps impact speed. They look like this-
View attachment 248919
View attachment 248921
View attachment 248922
View attachment 248925
6.5’s look like this-
View attachment 248937
View attachment 248940
View attachment 248941
View attachment 248944
I don’t know anyone that eats their game that is really happy with the tissue destruction that either one produces. If you buy a 30cal (or any caliber) and then choose a harder bullet to reduce tissue/meat damage, you’re literally ripping out spark plugs on your V8 to reduce its power...
As for distance traveled- the 178gr ELD-M from a 30cal magnum is about as close as you can get to a near guaranteed immediate drop from soft tissue only hits forward of the diaphragm of any commonly available projectile.