| 12-inch 40 caliber naval gun | |
|---|---|
 Fore turret of Andrei Pervozvanny | |
| Type | Naval gun |
| Place of origin | Russian Empire |
| Service history | |
| In service | 1896–1916 |
| Used by | Russian Empire/Soviet Union Japanese Empire German Empire United Kingdom Romania |
| Production history | |
| Designer | Obukhov State Plant |
| Designed | 1891–1895 |
| Manufacturer | Obukhov United Kingdom |
| Produced | 1895–1906, 1914–1917 |
| Specifications | |
| Mass | 42834 kg (1895–1906) 44250 kg (1914–1917) |
| Length | 12.192 m |
| Calibre | 12-inch (305 mm) |
The 12-inch 40-caliber naval gun was the standard main weapon of the pre-dreadnought battleships of the Imperial Russian Navy. Sixty-eight guns of the first production run were built in 1895–1906 by the Obukhov Works in Saint Petersburg. They were installed on seventeen battleships starting with Sissoi Veliky and Tri Sviatitelia and ending with the Andrei Pervozvanny class. A second production run was ordered to Russian and British gunmakers during World War I.