In a nutshell I agree with you. When the best bullets and best loads are compared there isn't enough difference to matter. I could include at least a dozen other rounds in the mix and say the same. Really, the jump from 308 to 338 magnum is a small one. To argue about any two in between is splitting hairs.
I also made the choice of 30-06 years ago. Have always felt I'd never give up anything but some recoil with a 270, but never saw enough difference to switch. Had I started with a 270 I'd probably be just as happy with it. In fact you can make a strong argument that since the 270 is more than adequate for anything the 30-06 will kill, does it with a slightly flatter trajectory and with less recoil that it is the better round. But as much as I like the 30-06 I find myself hunting more often lately with my 308. My 308 hand loads still beat 1920's era 30-06 factory loads by 200 fps and are within 100-120 fps of my best 30-06 loads. If a 30-06 in 1925 was good enough, 200 fps more from a 308 today can't be a bad choice. In this case it isn't about the chambering, I just like the rifle better.
I've observed a few details a bit differently though.
You might be right on the Remington part. I have observed over 100 fps difference between two 30-06 rifles, both with 22" barrels. With the Remington being the slower. In fact my 20" Winchester shot the same ammo 20 fps faster than my friends 22" Remington. That is a sample of one and you are the only other person I've run across that made the same observation so I'm not prepared too say all Remingtons are slower. But making comparisons like this with 2 different rifles can lead to wrong conclusions. The only way to reliably predict velocity loss from shorter barrels is to observe what happens to the same barrels as they are cut shorter and using the same ammo.
I don't load for 270, but 3000 fps with 130's from a 22" barrel should be easy with most guns. I have hit 3050 with 150's from my 22" 30-06 and a max load of H4350. Got the best accuracy with 1 gr less than max and still get 3015-3025 depending on the rifle. This guy only lost 114fps from his 270 when cut from 27" down to 21". This is typical of real numbers I see from both 270 and 30-06. You gain very little from barrels longer than 22" in either.
http://www.longrangehunting.com/forums/f19/short-barrel-magnum-velocity-19346/
You also didn't factor in for todays better bullets. They have made both calibers more deadly, and at longer ranges. With Barnes bullets the 165's and 168's would be too HEAVY for elk from a 30-06. The 150's at about 3000 fps would be about perfect with 130's @ about 3400 fps perfect for deer sized game.
Same for a 270. A 130 gr TTSX @ 3000 fps will give about the same trajectory as a 180 from a 300 mag. And do about equal damage on an elk when it gets there. A 95 gr 270 bullet @ about 3600 fps is a deadly deer killer.
A deer wouldn't. This is more of a factor with much larger game where penetration is needed. Better SD usually means better penetration, but you also have to consider bullet construction. It is not an exact science, and any old bullet will give more penetration than needed on deer. At least from these chamberings.
I also made the choice of 30-06 years ago. Have always felt I'd never give up anything but some recoil with a 270, but never saw enough difference to switch. Had I started with a 270 I'd probably be just as happy with it. In fact you can make a strong argument that since the 270 is more than adequate for anything the 30-06 will kill, does it with a slightly flatter trajectory and with less recoil that it is the better round. But as much as I like the 30-06 I find myself hunting more often lately with my 308. My 308 hand loads still beat 1920's era 30-06 factory loads by 200 fps and are within 100-120 fps of my best 30-06 loads. If a 30-06 in 1925 was good enough, 200 fps more from a 308 today can't be a bad choice. In this case it isn't about the chambering, I just like the rifle better.
I've observed a few details a bit differently though.
a great many 270's have 22" barrels...which drops the above muzzle velocities by at least 100 fps...and in some rifles (Remington) even more than that.
You might be right on the Remington part. I have observed over 100 fps difference between two 30-06 rifles, both with 22" barrels. With the Remington being the slower. In fact my 20" Winchester shot the same ammo 20 fps faster than my friends 22" Remington. That is a sample of one and you are the only other person I've run across that made the same observation so I'm not prepared too say all Remingtons are slower. But making comparisons like this with 2 different rifles can lead to wrong conclusions. The only way to reliably predict velocity loss from shorter barrels is to observe what happens to the same barrels as they are cut shorter and using the same ammo.
I don't load for 270, but 3000 fps with 130's from a 22" barrel should be easy with most guns. I have hit 3050 with 150's from my 22" 30-06 and a max load of H4350. Got the best accuracy with 1 gr less than max and still get 3015-3025 depending on the rifle. This guy only lost 114fps from his 270 when cut from 27" down to 21". This is typical of real numbers I see from both 270 and 30-06. You gain very little from barrels longer than 22" in either.
http://www.longrangehunting.com/forums/f19/short-barrel-magnum-velocity-19346/
You also didn't factor in for todays better bullets. They have made both calibers more deadly, and at longer ranges. With Barnes bullets the 165's and 168's would be too HEAVY for elk from a 30-06. The 150's at about 3000 fps would be about perfect with 130's @ about 3400 fps perfect for deer sized game.
Same for a 270. A 130 gr TTSX @ 3000 fps will give about the same trajectory as a 180 from a 300 mag. And do about equal damage on an elk when it gets there. A 95 gr 270 bullet @ about 3600 fps is a deadly deer killer.
I've never seen a deer care what a bullet's sectional density
A deer wouldn't. This is more of a factor with much larger game where penetration is needed. Better SD usually means better penetration, but you also have to consider bullet construction. It is not an exact science, and any old bullet will give more penetration than needed on deer. At least from these chamberings.