I get your point, and take it seriously, but with some of my rifles I go straight to testing myself instead of the gun. If there is a problem, then it is back to basics. This years sight in with a .30-30 before deer season was five shots standing at 50 yards. The test was appropriate for where and how I hunt with this rifle.
One shot don’t mean much fellas. We all get lucky from time to time. 3 shot group would be a better base line for accuracy. Just sayin 1 shot in the bull can be luck, 3 shots in the bull is confidence, 5 shots is accuracy.