Your carbide die is not stretching the case. If you doubt that, lube ten of them and run them through the sizer. The lube will reduce friction...see what happens.
You also said that if you fire the case and resize, and if it measures 2.070...you would rule out the die stretching the case.
IF that happens, the dies would have to be compressing the OAL. That is not going to happen on a straight wall case. Think about it.
