Most of us who do reload are extremely paranoid about primer position and make darned sure that the primer is correctly seated.
My guess the number guns that fired when the person closed the bolt is less than ten. Everyone who reloads knows about this.
You’re correct, quite obviously about primer seating. Law enforcement as a rule does not use reloads unless in a training situation, and unlikely then for the snipers because they typically shoot the same ammunition always, once a round is settled on.
Some people don’t know how to adjust a trigger, maybe that’s the problem here. 700’s used to have a pretty crisp trigger; don’t know about the new ones.
I think a sniper ought to have 3.5-4 lbs, not a bench rest trigger pull.