Instructions
Check the barrel of the Derringer before buying it. A true Derringer should have a wrought iron barrel. Solid steel barrels can be one way of spotting a replica Derringer pistol.
Look for specific traits that distinguish a Derringer pistol: a black walnut stock, a hammer piece that's checked, a trigger guard shaped like an "s" and a checkered grip.
Examine the mountings. Look for engraving that is gold, gold plated or German silver, and attached with pins to the stock. Only the butt plate and side plate fasten with screws or bolts.
Confirm that there are no serial numbers, but that the Derringer is stamped with DERRINGER PHILADELPHIA and perhaps the agent's name and even his address.
Measure the pistol's length. The true Derringer will be 3 ¾ inches to 9 inches long.
Research the date of the Derringer's manufacture before buying it. True Derringers were no longer manufactured after 1870. However, some companies made replicas of the Derringers that included the trademark stamp as well as many of the true Derringer's attributes. One such company was Slotter and Company.
Study the trademark stamps on the Derringer before purchasing it. To avoid trademark infringement, some companies made replica Derringers that had a slightly different trademark stamp. The trademark information can be a good way to spot replica Derringer pistols.
Bring the Derringer to a gun expert if you are still not certain whether you can spot a replica Derringer pistol. It is far better to be certain of what you are buying before learning after the sale is final that you own a replica that is worth only a fraction of the original.