"Here is a factory loaded cartridge without one, or a primer seated in the primer pocket."
I found one of those in a bag of new factory 6.5 Cr brass last year. Set it on the shelf as a reminder to LOOK at every piece of brass before doing anything else. I have a collection of broken depriming pins for proof of this importance.
For the OP: Back in the days of using 'primer only'(with an enlarged flash hole) indoor puff loads for practice, it was very important to NOT USE the altered cases for regular loads later. The results were often perforated primers or primer extrusion that tied up the revolver.