05-24-2020, 01:58 AM
+1 on rotating the cases while applying pressure. I have found that there can sometimes be an almost invisible deformation of the surface caused by the extractor or ejector. You can feel it when rotating the case carefully, and can see the deviation in the reading on the calipers. Also, if your cases have the "dent" on the lip, that can cause variation in the reading, depending on how you hold the case, and whether or not you rotate it while measuring. On my equipment, a fired case measures 1.217 base to shoulder(350 bushing). I bump back to 1.215 (0.002), and have had no problems, and brass holds up well.