Since Alec Baldwin killed Halyna Hutchins, multiple actors and actresses have come forward and stated that EVERY time they held a firearm on set they or the armorer pointed it at the ground and pulled the trigger six or seven times.
Therefore, any blanks in the pistol would be discharged, and need to be replaced with more blanks. If they just had dummy rounds in the pistol, it wouldn’t matter. But dummies don’t flash or go bang.