Jimro, or measure case wall thickness and compare its thinnest part to where the case was oriented in the chamber when fired.
That can be done by using the primer's finger print from the firing pin tip as a reference. Slowly extracting a fired case from the chamber then marking it's top point with a marker will indicate where the top of the case was in the chamber when it fired.
US Navy Distinguished Marksman Badge 153
Former USA Palma Team Member
NRA High Power Long Range High Master
NRA Smallbore Prone Master