Quote Originally Posted by Adrian II
Correct. As far as I know there are only two ways to stop a missile unit from firing if a target is within range: (1) move the unit physically out of range of any target, and (2) make the unit face away from all possible targets.

The latter is faster as well as safer (your missiles are close at hand if they are needed).

This knowledge may come in handy if you want to save ammunition at some stage (e.g. during a lengthy battle).
Err... I might be missing something, but when I need to stop may archers as they empty their quiver too quicly and I would have them wait a moment in order to shoot at the Royal Body guard commanding the enemy's army instead of a secondary unit, I usually toggle the "fire at will" off and click on halt, shouldn't it do the job?