Possession of a silencer that is not registered under federal law or of a bomb or similar device charged or filled with one or more explosives is prima facie evidence of a purpose to use the same to commit an offense.
Possession Of Unregistered Silencer Or Of Bomb Or Similar Device Prima Facie Evidence Of Unlawful Purpose
Mont. Code Ann. § 45-8-337, under Weapons.
Mont. Code Ann. § 45-8-337