A west-central Minnesota man who pleaded guilty to illegally possessing machine guns, pipe bombs and silencers has been sentenced to three years in prison.

Chad L. Monson, 46, of Willmar, was sentenced Friday on three felony counts in connection with the discovery of the arsenal on his property in February.

During his guilty plea in August, Monson said he knew he was barred from handling the weapons because of a previous drug conviction. Some of the weapons found at his home and at a nearby pole barn were once registered in a federal licensing database, but Monson admitted to letting their registration lapse. He also said he owned an Uzi machine gun illegally modified to fire in fully automatic mode.

A search by officers turned up 10 machine guns, two of them with obliterated serial numbers, three pipe bombs and three unregistered silencers.

Monson's brief plea hearing revealed no mention of prior allegations that he vowed to target attorneys and a judge with bombs, which factored heavily into a federal magistrate judge's decision to keep Monson detained before sentencing. Previous state charges cited an unnamed informant as disclosing the threats, and, at a June hearing in the federal case, Assistant U.S. Attorney John Docherty said Monson also made threats when authorities seized weapons and methamphetamine from his property this year.

Daniel Mohs, Monson's attorney, said his client was a gun collector who used the pipe bombs as part of his excavation business. Any talk of Monson planning targeted bombings, Mohs said, was "blown out of proportion."

Along with his prison time, Monson was sentenced to three years of supervised release.

Prosecutors had pushed for a prison term of 5¼ to 6½ years, but in arguing for leniency at sentencing, Monson's defense attorney noted in a court filing that his client "did well in school, participated in sports, helped his family and neighbors with farm tasks, and was an Eagle Scout."

The filing went on to point out that Monson "has lost everything" since being charged in this case.

"He has lost his company and career in the excavation business," the filing continued. "He had already lost his wife in 2012 during a 'very contentious' divorce that now leaves him with a debt to his ex-wife of $1.6 million. He hasn't seen his children since his arrest."

Paul Walsh • 612-673-4482