I heard a ceasefire call once on a range from the gun-bunnies. We were doing UAV ops with them spotting rounds when they said something like, "Check fire! check fire! check fire! "Lock up ring? lock the breach??" or something. The gun crews RAN out of the 155mm like it was about to explode about 50m away and got in Dress-right-dress formation.
Apparently a round was unaccounted for and thought to have left the range. You'd thought that they just shelled Lawton, OK or something. Everyones butthole puckered up real quick and we went on radio/phone silence and lockdown.
I never found out what happened, but an hour later, we were back at work.
Yup, happens all too often. The correct command is CHECK FIRE, CHECK FIRE and "To the rear of the piece, fall in". The gun crew stays there until the firing data on the weapon is verified and correct projectile, fuze and propellant charge is verified. Generally, if nobody's hurt and the round lands within the impact area, it's a learning moment with a brand-new Section Chief. The old one becomes "Local Security NCO" or some such.
If the round lands in some place near innocents/outside the impact area or heaven forbid, someone is killed or injured, whole different ballgame: courts-martial, relief for cause all the way up to the battalion commander and more.
Such is life in artillery - almost all of the rounds we fire are really lethal and once it's on its way, there's no bringing it back.