An Alaska man who owned high-powered rifles has been ordered to serve two years in federal prison, after he pleaded guilty to threatening to kill federal officials.

U.S. District Court Judge Ralph Beistline sentenced 52-year-old Wiseman resident Jay Rolf Armstrong after he made several threatening phone calls to federal officials, according to a statement from U.S. Attorney Bryan Schroder's office.

According to court documents, starting in January of 2016, Armstrong made numerous complaints over a three-month period to Bureau of Land Management officials regarding his denied mining permits. A year later, on Jan. 9, 2017, Armstrong spoke to BLM officials in Washington, D.C. expressing his anger about the denied mining permits. Two days later he began calling government officials, threatening to kill Alaska-based BLM employees. 

“We should just go out and kill these sons of bitches," Armstrong said. "Honestly, I have half a mind to walk down there and mess them up right now.”

Later, Armstrong called a BLM official in Fairbanks saying:

“Don't think for a second that if we don’t get this resolved that I won't pick up arms. I will pick up arms, and I will kill you guys. That's not a threat.”

The Federal Bureau of Investigation (FBI) and BLM conducted an investigation. Officials say they searched Armstrong's home in Wiseman. They said they could hear firing of weapons including a ".50-caliber rifle and a semi-automatic firearm."

Rifles firing .50-caliber rounds are typically large-bore sniper-style weapons such as the Barrett M82, an "anti-materiel rifle" with a range of more than a mile fielded by the U.S. military during Operation Desert Storm in 1991. Some police departments use the Barrett in tactical situations for its ability to penetrate brick walls, concrete and engine blocks.

"A search of Armstrong’s residence and property revealed a variety of firearms including rifles, shotguns, revolvers, rifle scopes, thousands of rounds of ammunition, ammunition magazines, firearm parts, gunpowder, shell casings, primers, bayonets and a large gun safe containing two .50-caliber rifles, additional firearms and ammunition," Chloe Martin, a spokeswoman for Schroder's office, wrote Wednesday.

Armstong entered a plea on Aug. 18 to two counts of threatening to assault federal officials. Beistline also ordered him to pay a $2,000 fine, and spend one year on supervised release after he leaves prison.