It is definitely a civil war era Colt .44 bulletmold for casting the "New-Model" of Colt revolver bullets. See photo below showing the specific version of .44 bullet your mold would make.
Something unusual about your bulletmold is that it never had the "sprue-cutter" which was attached to bulletmolds manufactured by the Colt company. The handles are shaped differently than on the Colt-made mold. Also, the holes for pouring lead into the mold are crude irregular openings, instead of neatly circular like on the Colt Company's version. See the other photo below (which includes Colt's patent-marking). Those three differences make me wonder whether your bulletmold might be a Confederate imitation of Colt's mold.