A 27-year-old Texas man pleaded guilty to participating in the theft of 650 guns from a UPS trailer in Springfield.
Quinton Haywood, of Glenn Heights, Texas, admitted to aiding and abetting others to steal the firearms in October 2017.
Haywood and others stole the guns and other cargo from a trailer at a UPS parking lot.
The firearms were being shipped from Beretta Firearms in Maryland to a Bass Pro Shops store in Springfield.
Haywood faces up to 20 years in federal prison.
Four other men were indicted in the scheme in January.