I emailed and asked specifically about ammo production since that was my original question, not reloading components. Here is the response a just received from Ryan:
Ryan Farr
4:28 PM (7 minutes ago)
to me
Tim
Most of the brass we use is Lapua or Norma and because that is not made in the USA we cannot use the Made in USA.
Thank You
Ryan Farr | Tech Support/Consumer Services Lead
Barnes Bullets
He answered my question simply and satisfactorily, without resorting to calling me a conspiracy theorist.
Thank you for the response Ryan.