Primer with no powder will do that. If you saw only a little smoke and didn't eject a case that spilled powder all over or wasn't packed with powder spoiled by oil or moisture, then you have some uncharged cases.
If your brass and bullet weights combined are more uniform than your charge weight is, you may be able to find suspect cartridges just by weighing them. In many instances, though, with fast target powders, the combination of mixed headstamp cases and cast bullets can vary more than the powder charge, in that case you could catch some, but not all of the bad ones. It'll requires a bit of work.
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