I have heard of people tumbling loaded rounds, but not unloaded and just primed. I would think you would be ok. I have tumbled live rounds before, not on purpose. I do though put .22 in the tumbler. .22 can be very dirty so if you tumble it for a just a short bit it cleans it and keeps the gun cleaner. Works too.
anyways I would think it would be an issue of getting something in the primer hole...but heck I don't really know.
If you have any casing that are shot and still primed you could just tumble them and see if crap gets in the flash hole? A little test.......
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