They weren’t exactly bullseye hits. He got the bullets in the right vicinity, which is admittedly an impressive feat, but it was pure chance that they managed to strike in a way that caused a lethal blow. If one was going through the effort of conspiring with 1-2 other gunmen, then it should have featured better and more intentional targeting, from spaces anywhere along the motorcade route that wouldn’t be so difficult to enter/exit. Or, if we’re talking about a broader planned conspiracy, use a blunter instrument like an IED or another vehicle, or both. Why opt for a sniper at all? The chances of success seem too little for a professional hit, but about right for an unstable radicalized former soldier looking for revolutionary glory.
Also, the car only started accelerating after the hit was made, and it was fairly axial to the bullet trajectory. I dunno know about you, but I can reload a bolt action rifle without dropping aim in under a second. It’s using the rifle as it was designed to be used.
It wasn’t a good shot. It was a lucky shot. One he clearly didn’t fully prepare to land, otherwise he probably wouldn’t have been arrested shortly after in a nearby movie theater. It was hardly sophisticated, and its success hinged almost entirely on blind luck and circumstance, which is the most difficult scenario to protect against.