The maker's name. if it's Pietta, is on the side of the barrel. Uberti is sometimes on top of the barrel, if it says Cimarron, it's an Uberti. If it says Navy Arms and is recent, it's probably a Pietta, older NA are Uberti. Uberti may be under the loading lever on the bottom of the barrel, as would be ASM (Armi San Marcos). Uberti's symbol, if not spelled out, looks like a ship's propeller, or a gear. If you find any other marks, describe them, we mmay figure it out.