DUDs 16%

[TempestV]

 

[AndyJWest]

An interesting video.

[Avimimus]

I read once that something like 25% of RP-3 rockets failed to detonate (at one point anyway).

[357th_KW]

This was even a problem with cannon shells.  There’s various stories and photos of airmen returning to base and having their ground crew find unexploded cannon rounds that were stuck in the aircraft.