Joseph Sweet received a nearly 16-year sentence for the thefts. Ronald Cook, the co-defendant, got 13 years.
The men stole the firearms last year from gun shops in Ottawa and Muskegon counties.
According to the U.S. Department of Justice in Grand Rapids, they exchanged many of the guns for drugs and also provided information that helped authorities build a case against the drug dealer.
Cook and Sweet were arrested in Muskegon County in July 2013 after breaking into Grasmeyer Bros. Gun & Supply and taking five handguns and four rifles.