Douglas Haig, 57, of Mesa, Arizona, admitted he made ammunition without a license. Haig came under investigation when armor-piercing bullets found inside Stephen Paddock's hotel room had Haig's fingerprints on them.
Haig has admitted selling 720 rounds of tracer ammunition to the shooter in the weeks before the massacre that killed 58 people. Haig's guilty plea involves the illegal manufacture of armor-piercing rounds.
Prosecutors said Haig operated a business, Specialized Military Ammunition, out of a workshop located at his home, advertised on a website, and sold ammunition at gun shows.
He'll be sentenced Feb. 19. The maximum is five years in prison and a $250,000 fine.