Just curious if its the last one that strays off? Or is it random? If its the last. I would say space the time between your shots a little more. Let the barrel cool a bit more.
If its only the one random of 5, then i would get the microscope on your loading technique - as mentioned runout, then myself I would make sure all brass is prepare the exact same (length, neck tension), bullets aren't deformed and weigh the same, and lastly powder dose to the 1/10gr or more if you're capable of.. I have done as mentioned and it does tighten things up - PITA, but the rewards are seen.
BTW, nice shooting! Despite the one flyer, still awesome!
Some people were telling me I should start reloading now to try and get more consistent.
Been shooting only factory ammo Sierra matchking 168 .308
I honestly think I am the problem here.
I think I need to relax more and think the shot through when I am behind the rifle