It's one of the very common reproduction Colt pistols made in Italy. This one made by PR and imported by FEI, from one online report I just read. A number of such pistols were made in Italy by various manufacturers with brass frames so as to be cheaper. Work OK with lighter loads and if not shot hundreds of times. Go online to Google and do a search for "PR and FEI and Italy", and start reading. Lots there, plus photos.
Appears from your photos that your gun has the original roll-stamped scene on the cylinder, but somebody has engraved the sides of the frame and the barrel. Maybe took off the markings and proof stamps to do the engraving. Simple engraving gives it a bit more value, tho brass frame repros are less valuable than steel frame. Maybe worth $150-175 instead of $100-120, I'd say.
To shoot a percussion revolver, provided it has a half-way decent trigger pull, use a common lead ball which hopefully is just large enough to shave a wee ring of lead off the ball as you press it into the cylinder, over about 10 grains volume of ordinary 3F black powder or Pyrodex P. An oversized lubed felt wad over the powder, say 36 cal. size, not only keeps the minimal fouling soft, but aids in gas seal for the ball. Put some ML lube or Crisco over the ball if you like, which also provides barrel lube. Little need for much lube with such a small powder charge tho. The lube is NOT to prevent "chain fire", which fact you can readily look up. Chain fire, which is rare, comes from loose or fallen-off percussion caps, so be sure you use the correct size caps for the pistol's nipples. They should fit snuggly and be rather hard to get off if not fired. May well be size 10 (smaller diameter) rather than size 11 as with most rifles and many pistols. But they DO need to press all the way down on the nipple by finger pressure or you will get misfires, only to fire on the second or third try as the cap is driven further down by the hammer fall.
Doing everything exactly the same every time is what gives pistol accuracy, and doing just that, plus shooting using both hands on a benched sandbag, will likely yield you surprising accuracy, even at 25 yds. Just squeeeeeeeeeze the trigger. But a little wind will readily blow round balls off the sighting spot.
Remember to never have your "helper" hand near or below the gap between cylinder and barrel. Always keep that hand rearward with any revolver, when shooting two-handed.
Aloha, Ka'imiloa
