Got a ton of experience with weapons and unless the air is thick and wet, a bullet will NOT leave a contrail. Just like an Aircraft traveling in the subsonic range (like an airline) will only leave a contrail at over 20,000 feet and then when it gets to about 35,000+ feet the contrail disappears.
Being supersonic doesn't mean a thing. It has to be within a certain altitude and speed and a 556 far exceeds to speed required.
You MAGAts sure do like making crap up. Now, unless the picture was shot at some terrific shutter speed (not very damned likely) the bullet wouldn't have been seen on film.
I don't take away that a bullet might have been used. But unlike you, I am not going to try and sell a clearly doctored Paint Shop. Here's a good on for you. When you are dealing with pictures, the entire picture will have about the same background. Not the case on this one. Someone used the wind feature of a paint shop to create the so called bullet and then blended it in the original picture. What they didn't do was to fake the background. The main Background is in circulars while the added fake graphic is linear.