Russian 1890s experimental 7.62 mm S&W revolver. I heard about Rachkov revolver, based on S&W No.3 in 7.62x38R Nagant. Barrel lenght 108 mm, overall lenght 248 mm.
Tokarev 1930. 
. AT Rifle. * #149
G6 7.62 mm experimental cartridge, 1938-41:
Other cartridge, also 7.62 mm:
U2 experimental rifle (sniper or light AT), 7.62 mm high velocity cartridge (G6 or other):
…
Data of high velocity cartridges:
7.62 mm:
G6 rimless - 950 mps
Rimless, from TKB-223 machine gun - 1250-1300 mps
Rimmed, from TKB-123 machine gun - 1400 mps (three variants of case - tupes A, B and V - Rus. А, Б, В (first letters from Russian alphabet))
Rimmed, other - 1450 mps
12.7 mm:
Rimless, from TKB-223 machine gun - 1200-1250 mps. 
. 
experimental SIG Gaetzi assault rifle of the 1937 model and presumably chambered for 7.65x38 mm.
Attachments
7.65x38.jpg
. 
. Rifle variants of Fedorov Avtomat:
6.5mm automatic rifle of Fedorov system, 1922
6.5mm automatic rifle of Degtyarev system with fixed barrel, 1922
6.5mm automatic rifle of Fedorov system, 1920-1922
6.5mm automatic rifle of Fedorov system with bipods, 1920-1922
7.62mm automatic rifle of Fedorov system, 1926
