Moore’s teat-fire .32
made in Brooklyn, New York circa 1860’s
The cartridge loads from the front, in an attempt to circumnavigate the Smith patent for a bored cylinder. The loading gate is open in the picture.
Acquired by National in the 1870s, and then acquired by Colt, I always believed this was the benchmark for Colt derringer production.
From The The Coonan Handgun Owners Group