Introduced circa 1914, the 2.7mm Kolibri is the smallest centre-fire cartridge of commercial manufacture and was designed for use in the miniature Kolibri automatic pistol. Barnes and Amber in Cartridges of the World have the following to say about it:- 'The 2.7 Kolibri could not be considered a humane caliber for hunting anything. However, it might do to dispatch a trapped mouse or elimimate an overly aggressive cockroach'