Only a few thousand were manufactured from the late 1870s to 1880s. The revolver has an exposed cylinder pin, scooped cylinder flutes and recoil shield on right frame has a semi-circular scooped out area to allow for loading cartridges. The left side of the frame is marked "MERWIN HULBERT & CO./NEW YORK U.S.A." followed by "38 CAL." The top of the barrel rib is marked with the two line Hopkins & Allen address/patent dates (1874, '75, '76 & '77). The barrel, left side of the frame under the grip, cylinder and right grip panel have the assembly number "725" with the serial number (602) stamped on the butt. Nickel finish with casehardened hammer and trigger and fitted with checkered grips featuring a raised dog head at the top. With correct factory box.