Jump the Gun

Etymology:

• It is noticing that in 20th century, the expression actually originated as “to beat the pistol”. It meant to begin a race before the pistol was fired by the starter. The expression was later changed to “jump the gun” that does not imply clearly what it makes, by replacing the word beat with jumps but perhaps the “u” letter that is in the word jump is also in the gun to make the phrase look catchy and interesting.