I read in Hodgdon Manual #27 that measuring case head or belt expansion can be a good means of measuring pressure. It says that for unbelted cases one should measure just in front of the extractor groove and that if expansion is 0.0005" then that would be considered maximum. For belted cases one should measure the belt and it should expand no more than 0.0007". The question I have is should this test only be done on new cases or only on once fored cases or does it matter? I would think only on new cases. Rufous.