pathfinder76,
The video's interesting, but it depends on what the purpose of the load is, the rifle, etc. etc.
One of my local friends is a 1000-yard benchrest shooter (which is a different game than F-class) who twice broke the world record for a 5-shot group. Both groups were around 2.5 inches--about 1/4 MOA. I can assure you he pays very close attention to every detail of his handloads, including bullet concentricity.
I got my first alignment gauge around 30 years ago, an RCBS Casemaster, and the instructions suggested that .003 maximum run-out worked best with varmint loads, and .003-.005 in big game loads. I have pretty much found that to be true, though often it varies depending on the rifle, especially with factory rifles, because their chambers and bores aren't as tight or precise.
If the chamber and barrel is a good custom job, it tends to makes more difference, even with factory ammo. One test I ran was with Hornady Light Magnum factory 7x57 ammo. The rifle was a custom with a tighter chamber/throat than usual, and as I recall a Hart barrel, and was going to be used on a Coues deer hunt in Mexico that was coming up quickly. Rather than try to work up a load, I decided to see how the factory ammo shot. (Coues deer are typically even smaller than pronghorns. The chest depths of the ones I've measured have gone 12-13 inches, from back to brisket, including hair--which means a vital area of about half that. Since they're often shot at longer ranges, accuracy does help.)
I'd purchased three boxes of the ammo at a store in Wyoming, which was loaded with the 139-grain Hornady boat-tail Spire Point Interlock. I sorted the three boxes by bullet run-out, to basically the same standards RCBS suggested, less than .003, .003-.005, and over .005. As I recall some of the rounds were up to .007 or so.
Then I shot a 3-shot group with each batch, in very calm conditions. The over-.005 group went 1.59 inches, the .003-.005 batch went 1.03, and the less than .003 batch .74. Shot another 3-shot group on arrival at the hunting camp in Sonora, which went around half an inch.
As it turned out I didn't have to shoot at 400+ yards, but only around 220. But if the shot had been at 400, the over-.005 ammo would have grouped around 6 inches MINIMUM at 400. Theoretically this is good enough for 6-inch vital area--if the shooter's hold is perfect, and wind isn't a consideration. Have made the same sort of tests in varying mounts of wind, and even a pretty mild breeze, say 5 mph, can increase group size by at least 50%, especially in mountainous country, where winds can go in any direction.
Some target games require more accuracy than others, and not just 1000-yard benchrest shooting but "short-range" bench shooting. My 6mm PPC benchrest rifle will consistently put 5 shots into less than .2 inch with its best loads, and has averaged .15 during some load work-up, in perfect conditions. But it will NOT do that if bullet concentricity is over .0005 inch--and that is NOT a misplaced decimal. That's the maximum run-out of my handloads. With even .002 runout, group sizes double.
I also prefer minimum run-out in my varmint loads, especially for burrowing rodents, because even a big prairie dog isn't wider than 3 inches--which is a pretty small target at, 500 yards. Young Richardson's ground squirrels are often only an inch wide--a pretty small target at 300 yards. To be able to consistently hit them, even in very little wind, requires sub-half-inch accuracy at 100 yards. And yes, I try to load so bullet run-out is .002 or less, because have found it does make a difference, even at only 200-300 yards in typical wind conditions.
Should also point out that the 3-shot groups many big game hunters typically shoot do NOT reflect the average widest spread of a rifle and load. Five shots come closer to maximum spread, and are what I shoot when accuracy really matters--because 5-shot groups average about 1.5 times as large as 3-shot groups. (Statistically, 6-shot groups tend to show a rifle/load's realistic maximum spread slightly better than 5-shot groups, but shooting them would confuse readers.)
