The parent case is the 30/06, 338/06, 8/06, 270 W, 6.5/06 and 25/06 case dimensions are ABOUT the same, Except when necking the case up to 35 Whelen and 338/06 etc, when necked up the case length shortens and when fire formed to an improved design will shorten more. When the neck is necked up it shortens, when necked down the neck lengthens, the only time it matters is when the person forming the cases has a choice of cases and has the ability to keep up with the numbers.
The case length of the 270 is longer than the 30/06, the neck is longer by - or + a few but about the same length, the case length from the head of the case to the shoulder is the same but the 270 is longer by .041 thousands, and the shoulder angle is the same, this makes the 270 shoulder longer by about .040 thousands.
F. Guffey