Dustin Pacheo appeared in provincial court Thursday, a day after Mounties investigating a report about a firearm instead discovered a launcher.
Const. Gary O'Brien says two women who were also arrested in relation to the device have been released with no charges pending against either of them.
Pacheo is charged with unauthorized possession of both a firearm and an explosive device.
O'Brien says investigators are still trying to determine the origin of the grenade launcher.
Police have met with Canadian military officials, who say the item is not part of their weaponry.