The 25×35.5mmR is a rimmed WWII-era flare gun caliber developed by Nazi Germany for use in the Kampfpistole.
When the smoothbore barrel of the Leuchtpistole proved inefficient for its intended role, the Germans took the Model Heer 36 and Model Heer Leuchtpistoles and converted them with a new 25mm rifled bore. This lead to the creation of the Leuchtpistole Z, also known as the Kampfpistole.
The 25×35.5mmR was designed specifically to fit into and to be fired from the aforementioned 25mm rifled bore. However, they are also usable in an unrifled Leuchtpistole.
- Spgr.LP (short for Sprenggranate Leuchtpistole, meaning "explosive-round signal pistol") - A 12.5cm long high explosive round with a small black powder charge and a muzzle velocity of 60 meters per second.
- Nebelpatrone Z - Smoke cartridge, either with or without vents.
- Deutpatrone Z - Also known as the Rauchsichtzeichenpatrone, it is a smoke cartridge designed for use in conjunction with the Nahverteidigungswaffe system mounted on German tanks.
- Nachrichtenpatrone Z - Cartridge designed for sending written messages.
- Leuchtpatrone Z - Signal flare round.