1. New brass will chamber and extract.
2. Fired brass will chamber and extract.
3. Resized brass will chamber and not extract.
4. Brass is in saami spects, but you cannot measure the difference between 1 & 3, or 2& 3??? Do not rely on a Wilson case gauge, or other similar tool. What matters is the way you setup your dies for the rifles chamber and that your brass is shorter than the rifles chamber. If fired brass chambers and extracts like new brass I would be neck resizing only.
