As promised, here are pics to illustrate concepts. For grins I sometimes take apart range pickup ammo. Here are bullet dimensions after a "heavy taper crimp". Not shown is the fact that the bullet creeped forward in the case from chambering. This had a light primer style and was likely a dud that got racked out.The heavy crimp can mean that neck tension is compromised. The bullet swages and brass springs back. I'll post a pic later to demonstrate.
.451" bullet. Note the various measurements.