Those were some wonky setups I saw those guys using. They're not testing the accuracy of the rifle. They're testing the accuracy of the rifle/shooter/ammo combination. The probable lack of a developed load and the soft mushy part dick with the results.
That said, most factory rifles still won't shoot MOA with any regularity.
To actually test the rifle, you'd need a proper bench, heavy pedestal rest/rear bag combo with correct bags for the stock, all the extraneous crap taken off the rifle and a developed load. Plus a proper scope so you can actually see the exact point of aim for repeatability. And I don't mean "I-can-see-the-bullseye" scope. I mean the "I'm-aiming-at-2-o'clock-on-that-bullet-hole" type mag/res.. You can't aim at what you can't see.
..We used to setup at the GSO show with varmint and BR rifles. Some had test targets. We'd get that crap from some passerby's about they could do that all day with their "Tacticool Shnaufer-Hauzen Sooper Sniper Rifle with an Of-ficial NC Star tactical-plex LPVO".
Ok, Francis.. We're just doing these things cause we
really like the "
recycled bowling ball" look on a rifle.
🤣