***** NOT A TEACHER *****
Good morning, Sumon:
(1) You have asked another great question that has kept me awake all night!
(2) I may (repeat: may) have found at least one answer.
(3) Look at these sentences in one scholar's book (Introduction to the Grammar of English by Rodney Huddleston, page 173 in a 1985 reprint):
(a) If you do that again, you will be fired.
(b) If you do that again, you are fired.
The scholar says that sentence 3b reflects "greater assurance." I guess that indicates greater certainty about losing your job.
(4) Here are two of my bad examples:
(a) If you do not eat up all the broccoli, you will not get any dessert.
(b) If you do not eat up all the broccoli, you do not get any dessert.
If I understood Professor Huddleston's book, maybe 4b expresses with more certainty the consequences of the little boy's refusal to
eat the broccoli.
(5) Now let's consider your two sentences:
(a) If you don't hit the target, you won't score.
(b) If you don't hit the target, you don't score.
Let's say that you are applying to be a police officer. You are on the firing range in order to prove your ability to shoot well. Maybe
the officer-in-charge would say 5b to stress the certainty of the consequences of not hitting the target.
*****
I found Moonlike's comments very interesting and thought-provoking. It seems that books do not usually discuss this matter very
much. I am very eager to see what others have to say.
HAVE A NICE DAY!