Dejan Hercegovac had been scheduled for sentencing Monday, but U.S. District Judge James Teilborg has reset sentencing for Oct. 15.
He has pleaded guilty to a charge of conspiracy.
Hercegovac admitted buying 31 guns for the ring and saying that the guns were for him when he was actually making the purchases on behalf of the ring.
He faces a maximum sentence of five years in prison.
Authorities have faced criticism for allowing suspected straw gun buyers to walk away from gun shops with weapons, rather than arrest the suspects and seize the guns there.
Copyright 2012 The Associated Press.