A federal jury on Monday afternoon found Terry Honeycutt guilty of 11 of 14 counts of selling meth-making materials at the family's Brainerd Army Store.
He was immediately taken into custody and will be sentenced by Judge Sandy Mattice on May 12 at 2 p.m.
One of his convictions was for conspiracy of selling an iodine product used in making meth. Other counts involved sales on specific dates.
He was found not guilty on three counts.
The jury deliberated nine hours over two days.
His older brother, Tony Honeycutt, earlier pleaded guilty.
He was sentenced to five months in federal prison and five months of home confinement. He must also make a $200,000 forfeiture.
Judge Mattice will hold a hearing to determine the forfeiture amount for Terry Honeycutt.