These modern small size automatic pistols are built on a mistaken idea that they are the modern prototype of the old Derringer pistol, which was the most deadly pistol in existence, and the weapon used most frequently in old-time saloon shooting quarrels.
The Derringer was a vest pocket pistol smaller and more compact than most vest pocket automatic pistols, but it was not a small bore pistol. (See Plate [11]).
It was just the essential parts of a big powerful pistol, shooting a big powerful cartridge.
The want it fulfilled was a pistol having great power in a small compass; one shot was all that was required, as the shot was fired at very close range.
Some Derringers had a second barrel below the other, but the typical Derringer was a one shot pistol.
Now if you take a big single shot pistol, how would you reduce it in size to fit the waistcoat pocket?
First you would cut off the barrel except the actual chamber in which the cartridge lies.
Then you would take off as much of the hammer as is compatible with leaving enough grip for the thumb in cocking.
Then you would whittle away all the stock till only the lock mechanism remained; and this was practically what the Derringer was.
This could be still further improved upon by making it “hammerless”; that is with an internal hammer.