We ALL know what Elmer used - that was not asked.

This is what the brass supplier said about the brass they sold or recommended for the .400 Whelen.

"The .400 Whelen Basic is supplied as "Cylindrical". It is intended for use as a wildcatter's case to form many different .30-06 / .308 family wildcats from. The case neck will need to be reamed or turned after final forming."

That is why I addressed the turning and reaming question in the manner I did.

If this SUPPLIED brass has thick necks, they will get thicker when necked down - will they be too thick? That remains to be proven.

if they are used for the .308 family, they will indeed need turning or reaming.

I also addressed why turning was the preferred method over reaming.