Tarn is a semiautomatic pistol designed by Zygmunt Stanisław de Lubowicz-Bakanowski at Swift Rifle Company of London. The gun was engineered during WWII, at the time when Swift Rifle Company was specializing in production of training aid devices for the army. Tarn is a blowback operated weapon which fires from a closed bolt. Gun has firing mechanism with hammer and trigger mechanism with a disconnector for single shots only. Pistol is equipped with manual safety. Tarn is a quite rare blowback operated pistol designed for powerfull 9x19mm Parabellum cartridge. Gun has heavy slide and very strong recoil spring. Magazine well is located in pistol grip. Magazine latch is located under the grip and locks against the bottom of magazine. Breech and top of the slide are separate parts keyed together by large cotter pin. Barrel is keyed with frame by soft pins. Arrangement of hammer nad safety axis requires care in assembly of the pistol to ensure that other parts are operative. Finish of specimens submitted for qualification testing by British Army was of low standard. During the test by Commission of the Army Supply in 1945 pistol exhibited low accuracy and was difficult to reload. After the tests pistols were sent back to Swift Rifle Company along with a copy of negative report. Report was written on 13 April 1945. Tarn pistol was never entered in military use and its production never commenced. Probably after WWII seven Tarn pistols were sent to gun collectors in the USA.
Source: "O.B. Investigation No. 1,763, 9mm, self-loading pistol, TARN" report from Archives of Royal Small Arms Factory, Enfield, United Kingdom. Thanks for help by George Kujawa (Phouty).