I've been watching this conspiracy theory which is an analysis of two separate videos of the shooting in different locations, the first near the stage and the second somewhere further away. In the second video it's clear that the first three shots, or at least shots two and three, are not from the same weapon that fired the 4th-8th shots. But in video 1, shots 1-3 and 4-8 have a similar time delay between the sonic boom of the bullet as it hits the microphone and the sound from the bullet being fired. (Remember the bullet travels faster than sound, so the sonic boom is heard first near the target.)
His conclusion is that both weapons were fired at the stage, ruling out the second weapon being the counter-sniper's.
So two shooters. The sniper shot that killed Crooks was about 10 seconds after the first 8 shots.
https://youtu.be/LouUbMYb7Bc?si=mdEF0rZXkrz9WTz2