That is not entirely accurate, My chamber cast has the exact dimensions as the original Ackley drawing and I blow primers. When I contact Nosler they tell me that, yes, using the Nosler cases out of the box, in traditional chambers creates too much headspace. Redding also stated that yes, there was a reason for the +.014 shell holder and yes, the early dies were different than the SAAMI dies. I have read a lot of articles by people stating there is no difference but that doesn't explain why, when Hornady, Nosler and now Federal factory loads are shot in traditional / early chambers, it causes primer / high pressure issues. There have been way too many instances of it to not believe there is a difference in the two chambers. If they were the same, why not use the traditional reamer still today for SAAMI chambers ? Your statement would imply that they would be the same reamers. It's not internet rumor when ammo manufacturers and die makers tell you, there is a difference.