Secret howitzer

The 95 mm howitzer M1753, called secret howitzer or Shuvalov's secret howitzer, was an 18th-century Russian cannon, a type of muzzle-loading howitzer, devised and introduced into service by artillery commander, General Peter Ivanovich Shuvalov.

Shuvalov's gun had an unusual, oval bore, which was designed to facilitate shot dispersal while firing canisters and therefore to increase the beaten zone. A special canister round produced for the cannon contained 168 balls; a grapeshot version, with 48 larger balls, was also provided for shooting at 300–600 yards distance.

The name of the gun comes from the great secrecy which surrounded it. While not in use, the muzzle was covered with a lid to hide its unusual shape. The death penalty was set as the punishment for revealing the secret of the weapon.