Hi. I should have said 22" to 24" for a .30-06 is standard. As per your suggestion. You really want to handle several rifles with different barrel lengths to get the feeling of them.
"...commonly needed to achieve the full velocity potential..." For a 7mm Rem Mag, sure. A 7mm Mag isn't a .30-06 though. It runs at much higher velocities with like bullet weights. 3110fps vs 2910fps muzzle velocity with 150 grain bullets. Mind you, there's a 2" difference in barrel length and 150's aren't used often in a 7mm. A 7mm will have more muzzle blast, flash and felt recoil too. It's not really a good comparison though.
Rem 700's in 7mm RM come with a 26" barrel. A lot of it has to do with the rifling twist. A .30-06 usually has a 1 in 10 twist. A 7mm, a 1 in 9.25 twist.
Wikipedia isn't a great source for info. Anybody with internet access can post there. A lot of internet inspired nonsense gets repeated there.
Go here to compare cartridges. Compare like bullet weights and construction.
http://www.remington.com/products/am...on/ballistics/