Historical History of Concealed Carry: Deringer’s Derringer, .41 Caliber Fun by Dan Zimmerman | Jun 25, 2018 | 8 comments Did you know that Deringer was the man — Henry Deringer, Philadelphia gun maker — and derringer is the gun? A .41 caliber ball from this little beauty would have gotten someone’s attention. Logan Metesh on a classic pocket pistol . . .