There are two ways to do wall shot :
1. Point a gun at a wall and shot.
2. Be close to a wall and press F to make gunpoint penetrate wall. (Using bug)



In the video, AK 47 is the case 1.
However, m16 can be passed through a wall by only the case 2.
That is, some weapons are not allowed to do the first way.
The next section is for the details of each weapons.

Red is case 2, and blue is exceptional.

Here is a video about how to use wall shot.