I'm sorry. I wasn't clear with one of my earlier statements. The .35 Whelen and .30-06 share the same case length. But, you cannot achieve the .30-06 case length by forming .35 Whelen from '06. In order to achieve the standard 2.494-2.504" case length of .35 Whelen, you must start with a case of .30-03 length. (when you expand the neck to .35 caliber, it gets shorter)
However, thanks for pointing out the slight neck difference between the 30-'03 Springfield and the very slightly shortened case neck of the 30-06 to make a technical point even if it has no practical application for the proper functioning of the cartridge.
There are very important, practical applications for having the proper neck length. It may not effect most shooters, but it is very important to some people. I covered it in a previous post:
FrankenMauser said:
Under most circumstances, that difference is trivial. But, there are times when it really matters. For example: Shooting certain styles of cast lead bullets, or paper-patched bullets, with .30-06 brass formed to .270, .280, or .35 Whelen can result in significant fouling or bullet damage. The bullet needs the longer neck {of the .30-03} to protect it from damaging the bullet or paper patch.
The same applies to .270 Win and .280 Rem. You can create perfectly usable cases by forming from .30-06, but that doesn't change the fact that .30-03 is their proper parent cartridge; or that you
do need that long neck when shooting certain types of loads.
Saying .30-06 is the parent cartridge for .270 Win, .280 Rem, .35 Whelen, and .400 Whelen, is like saying .303 British is the parent cartridge for .30-40 Krag. Sure, you can form a perfectly usable, short-necked .30-40 case from .303 Brit; but that doesn't make it the parent cartridge.
Side note:
Don't EVER believe the parent cartridges listed on Wikipedia. Most of the "knowledge" there is derived from the same sources as the "knowledge" on TFL: Gun writers that spew worthless dribble, and manage to turn it into "fact". Those "facts" are then cited on the Wikipedia pages, and lead to discussions like this one. And, of course, you also have complete idiots making changes.
Some examples: They currently have both .30-06 and .30-03 listed as the parent for .35 Whelen. They occasionally have 7x57mm listed as the parent for .308 Winchester (it was originally based on .300 Savage). Some one likes listing .22 LR as the parent of .22 WMR; and .22 WMR as the parent for 5mm Remington. And, .45-70 sometimes shows up as the parent cartridge for .30-06.