Warbadger posted:

You can gently caress somebody up with blanks just in general. Debris from the blank, squibs or obstructions of any kind in the barrel, or just plain being too close to somebody.

Edit: Also using old, hot loaded, or incorrect types of blanks. There are pretty hot loaded blanks meant to do things like lob rifle grenades long distances that you REALLY do not want to be out in front of.