Two things, first maybe it is just the picture but it does not appear like your 30 cal insert is all the way seated - sort of canted. And second are you SURE that when you insert the hammer bullet to determine the COAL that it is fully inserted to determine the max depth or COAL. I have been using the same system a long time, since back when it had just been developed by Stoney Point and sometimes the little thumb screw will hang up on the inserting rod so that it feels like the bullet is touching the lands when it actually is not. This would result in too short of a reading. It is also possible to push too hard, resulting in too long of a measurement. I take MULTIPLE readings and then take what appears to be the most common/average. Sometimes one or two of my readings will be way off and therefore obviously in error. It is a good system but there are multiple other ways to come up with the info you need. I find the Sinclare system hard to follow. As noted previously, make sure your cases are less than max length. Good luck.