Hangfires were much more common in the old days, seldom seen today, but it still happens sometimes. I've had a couple in my life, I think the longest was maybe 3 seconds, but it was many years ago.
We used to be taught that in the event of a failure, to wait, slowly count to
30 (NOT 10) then eject the dud round. (obviously not to be applied when some one was shooting at you, or might be...)
They are rare, its much more likely to be a complete dud than a hangfire, but hangfires can, and do still happen, it pays to wait.
so talking about these hang fire rounds got me thinking, I probably have 200+ rounds left, can I pull these bullets, trim the case, and reload? does the primer need replaced or is it just bad powder?
If you are talking about the Czech ammo you mentioned before, the primers are most likely Berdan, and not worth replacing (assuming you can even get replacement primers). The problem could be the powder, it could be the primers, or it could be both. Pull the bullets for resuse and pitch the rest.
If the cases are boxer primed, you could reuse them, but get rid of the primers (and the powder), as they are suspect.