Integra uses a Walther PPK as her personal sidearm. It's (sometimes) loaded with a fictional incendiary mercury round. It's seen various times in "Master of Monster" in flashbacks.
Profile[]
The Walther PPK was manufactured in 6.35mm auto (.25 ACP), 7.65x17mm (.32 ACP) Auto or 9x17mm (.380 ACP).
While the K would commonly stand for kurz, German for "Short", PPK means Polizei Pistole Kriminal, the Criminal Police Pistol, noted by its compact size. The Walther PPK is a shortened version of the Walther PP. Since it was the most common compact pistol of WW2 (for the German forces) it is the most famous as well as being the weapon of choice for fictional British Intelligence (MI-6) officer 007 James Bond and suicide weapon of Adolf Hitler.
The Kriminal in the PPK's name refers to the fact that the gun is issued to the German Criminal division (Kriminalpolizei), the criminal investigation agency within the German police system, which would be termed 'Detectives Division' in most U.S. police forces. Just like most patrolmen in the USA carried a 4 inch revolver at the time, and the Detectives often carried a snub nose revolver suitable for concealed carry (Colt specifically calling theirs the Detective Special) so too did the investigative branch of the German Police desire to carry a smaller version of the full sized patrolman's duty weapon.
Usage in Hellsing[]
Integra was first seen using this weapon in Episode 2 "Club M" training and later again in "Dead Zone" shooting Jan Valentine with incendiary mercury rounds. Richard Hellsing, Arthur Hellsing's younger brother and Integra Hellsing's uncle was seen using this in a flashback on Episode 10 "Master of Monster".