This is a rather strong example of a late original Iron .31 Caliber Colt Bullet Mold that once belonged to a Model 1849 Pocket Revolver. This mold is listed as M#20 on pages 125-126 of the late Robin Rapley's book titled Colt Accoutrements 1834-1911. This book is a must have for any Colt collector and the items he was able to document from advanced collections, especially the early Paterson accoutrements, have reached such values that they would be very difficult to track down and write such a book in today's world. If you ever had the opportunity to meet Robin at one of the many shows he used to attend, you could not meet a nicer human being. Sorry to get nostalgic but every time I get an old Colt mold or flask, I pull out his book and you can almost hear his Kiwi accent as you read the pages. So let me tell you what Robin thought about this specific mold type! He notes that the sprue-cutter is marked "COLT"S PATENT", the right block will be found with "31PKT stamped across the top....the ball nearest the hinge and a heeled conical...The mold is correct for the 1849 Pocket model from late 1856 onwards, and for the 1855 New Model Root Revolver in .31 caliber, manufactured after 1860. But he goes on to break this down a little further because on the following page, Robin has a photo of a mold almost identical to this one that he further elaborates upon as having all the characteristics of the late production molds. He notes, thicker sprue-cutter plate and notice how much thicker the legs have become and meet below the sprue-cutter. Another thing Robin would mention on these late Colt molds (which applies to all caliber molds from this era) is how the right edge of the sprue cutter has a more square-shaped profile than the earlier ones which were more rounded. Robin notes that these late features show up in the mid-1860's. So this mold is the late iron type and correct for mid-1860's up to the end of production in 1873.
Overall Condition grades to NRA Antique Fine with 65% original blue that is mixed with scattered spotting and some light corrosion. When you start getting back to antiques that are 150 years old, they're almost always going to show a fair bit of use and A LOT of oxidation. So that said, to find one that has survived with most of its original blued finish, albeit a little splotchy, is exceptional for this age. Not only that but it has sharp edges, great markings (COLT'S PATENT and 31 PKT are clear) and excellent conical and round cavities. In fact, the cavities still have most of their original blued finish. In spite of its age spots, it shows very little if any signs of real usage. For example, there are none of the usual tapping marks/ding on the sides of bottom associated with the user trying to split the cavities back open to retrieve the cast lead bullets. Furthermore, everything is very tight and the handles show no bends. This would make a great accessory to a late Model 1849 Pocket or Root Revolver in Fine Condition and would go well with a cased gun.