With a mechanical timer there is no relenting, it is Fate, and if you cannot make a good shot in time, your score is spoiled. This trains you properly; you are not buoyed up by false ideas of your skill which, when there is real timing, will prove that your ideas of your skill are vain delusions.
In England a clock is used, marking seconds or half-seconds.
This is very good for the man who works the targets; he sees if he is working the time right, but it does not assist the shooter as he does not hear the time being struck.
For the learner, it is important that he should be able to apportion his time, take so long for lifting his arm, so long for aiming, etc., so as to learn how to do the best shooting in the time limit allowed, and judge accordingly.
For this purpose there is nothing better than the metronome.
The metronome is used by music teachers for instructing their pupils in the right time when playing.
Music for instruction is marked with the metronome beat proper to it: all that has to be done is to wind up the metronome, set it to that number, and start it beating.
A metronome consists of a pyramidical box with clockwork, which makes an upright pendulum beat at whatever speed it is set.
The speed depends on a weight which is moved up and down the rod, to set marks, which correspond to numbers engraved on the sides.
It is, in fact, a clock pendulum reversed.