An automatic or semi-automatic firearm having an indirect gas operating system, the firearm having: a receiver; a bolt assembly slidably received within the receiver; a barrel having a bore, the barrel coupled to the receiver; a gas block mounted to the barrel, the gas block having a cylinder in fluid communication with the bore; a rod coupled to the cylinder and having a striking rod; wherein gas discharged from a fired cartridge displaces the rod and causes the striking rod to strike a striking surface of the bolt assembly, wherein the gas repositions the bolt assembly in bore.