That's too funny, people get a little odd when it comes to these things, both are excellent calibers, I've shot each side by side from my deer stand at 200-300 yd ranges, both are very effective on whitetail, now whether you prefer one or the other, might just be a matter of preference, based on what ammo you are shooting and what rifle you are putting it through.
I would have to refresh myself on the loading tables and ballistic performance, so many variables with these, and most small arms/ammo/reloading. I would think you could make that '06 overachieve with the extra space for powder, depending on what you shoot it through, type of bullet etc. 7.62mm/.308 has some minor variance in casing wall thickness, this effects the powder capacity in the casing, I remember this from reloading these. I am thinking that thickness correleates to 2 reference standards used for ammunition, I would have to research that. One of the reasons I'm aware of it is from reloading for a Springfield M1A, it's full military specification, definitely some things to know about there, including headspacing, I had to make a dummy round to shape the case and make sure it fit the chamber, bolt closed correctly, think that was 1x fired .308 brass, not military brass, which I think are berdan primed, thicker casing wall, not so desirable for reloading.
At least with military ammo,they are supposed to be identical, but I don't know off hand what the max effective range is for the '06, .308 in military ball ammo is 460 meters. The .308 is at zero drop around 290-300 yards, but again, it depends on what you are shooting. I took a whitetail at about 250 yds this year with the M1A, 1 shot, left about 4" space over the top of the shoulder, and it hit the lung area, was sighted in at 100 yds, so I might have had to over compensate, but based on how it was shooting, I had a good idea where to place the crosshairs, the bullet drop was perfect from where I compensated.
I, as would most, prefer those flat shooting ballistics, am curious as to how these compare and at what ranges with various hunting loads, never really got into any extensive comparison, probably all kinds of published data on each though. I'm thinking hotter loads, with lighter bullets would work well, I've done 130 gr hollow points w 3031 IMR powder, per loading tables and gotten excellent results from my M1A in .308. That ammo placed in the vitals does a good job, have taken quite a few with those.
I like the .30 caliber size, because of it's versatility, (as well as availability- and that seems to be changing) nice range of loads and bullets to use. I realize other calibers like .270, and some smaller ones can or are just as effective, they certainly have high velocities and flat trajectory, makes an excellent caliber for whitetail. My friend just bought an M77 stainless steel Ruger in .280, be interesting to see how that shoots.
