The .300 Win Mag ammunition will be manufactured Sig's ammunition facility in Jacksonville, Arkansas, according to the release.
https://www.military.com/daily-news/2020/01/14/army-picks-ammunition-maker-its-new-sniper-rifle.html
https://www.military.com/daily-news/2020/01/14/army-picks-ammunition-maker-its-new-sniper-rifle.html