Question

why gun is always tilted slightly about the target

Answer 1

U must be knowing that a gun recoils when it's fired.

Recoil means that the gun jer.k of from the users hand when a bullet is fired from it.

This happens due to the third law of motion
Which is -
Every action has an equal and opposite reaction .

So as to perfectly aim after jer.king , the gun is shifted slightly.

Answer 2

It is because of Newton's third law of motion
The reason is that when the gun is fired the bullet in it move ahead by the spring which gives force (action). Simultaneously the gun recoil backward but the force (reaction)