I was wrong - the new record, shot this year at a registered match was 1.058" for 5 shots & it was with a 6BR Ackley IMP. As well, it was shot on a scoring target and made 50 5X.

http://bulletin.accurateshooter.com/2018/07/0-1-moa-at-1k-amazing-1-068-50-5x-group-at-1000-yards/

World Record-Setting Cartridge and Load
Mike was shooting a 40-degree Improved version of the 6mmBR Norma cartridge. Long popular with Benchrest and 300M shooters, the 6mmBR was the original inspiration for this website. Yep, we started as www.6mmBR.com. The Improved version has extra capacity, allowing about 100 FPS more velocity when chambered with a long throat. For his record group, Mike shot Vapor Trail 103-grain bullets in Lapua brass. He loaded Hodgdon H4895 powder with CCI 450 (small rifle magnum) primers.

lol- not even BR4's.