A cultural appreciation for recreational shooting runs deep in the region.
Mark, a former Dauphin mayor, was arrested during a police search on 7 July.
He appeared on a dozen charges in court last week and was released from custody with conditions.
“The illegal trafficking of prohibited weapons is a serious offence that threatens public safety,” RCMP Assistant Commissioner and Manitoba Commanding Officer Scott McMurchy said on Monday.
“We thank the many RCMP officers who are working on this case for their tireless efforts in targeting individuals who are trafficking these dangerous and illegal weapons and bringing them to justice.”
The investigation began in March when police were notified of firearms charges in the US against another Dauphin-area man.
That investigation led RCMP to find and seize firearms allegedly purchased by Mark, which police said were “never lawfully transferred”.
At least three firearms are believed to have been illegally trafficked and one firearm had its serial number tampered with, officials said. They also found more than C$300,000 (£158,000) in cash at the home.
While the motive is unclear, Manitoba RCMP Cpl Barry Kirby said at a news conference on Monday: “We know he’s a firearm collector, but that’s really all that we know.”
Mark was elected mayor of Dauphin in 1994 and lost a re-election bid in 2010.
In parliament, he represented a constituency now known as Dauphin-Swan River-Neepawa from 1997 until 2010, when he resigned from the House of Commons.
He has been a member of the Reform Party of Canada, the Canadian Alliance and a Conservative, and unsuccessfully ran for the seat again in 2015 as an independent.
