The Welrod was a British bolt action, magazine fed, suppressed pistol devised during World War Two at the Inter-Services Research Bureau (later Station IX), based near Welwyn Garden City, UK, for use by irregular forces and resistance groups. Approximately 2,800 were made.

It was used primarily by the British SOE but was also used by the American OSS. The Welrod, also known as the "Assassin's Pistol", was extremely quiet for a gun, producing a sound of around 73dB when fired[1]. Examples were made in 9 mm Para and .32 ACP, with capacities of five and six rounds in the magazine respectively. The Welrod took the form of a 1.25 inch diameter cylinder about 12 inches long[2]. The rear of the cylinder contained the bolt, the middle the ported barrel and expansion chamber of the suppressor, and the front the baffles and wipes of the suppressor. There was a knurled knob at the rear that served as the bolt handle, and the magazine was also the grip. Removing the magazine/grip made the weapon easier to conceal.

The Welrod was provided with sights marked with fluorescent paint for use in low light conditions. Although it had a maximum range of 23 meters, it was intended for use far closer—up to point blank. The muzzle end of the gun was cut away so that it could be fired in direct contact with the target. This would reduce the sound levels even further, and removed the chance of missing.

The ported barrel of the Welrod served two purposes; it released the powder gases gradually into the rear of the suppressor, reducing the sound of firing, and it reduced the velocity of the bullet to subsonic speeds (especially important in the 9mm version since the standard 9mm loading is supersonic). The baffles and wipes that follow the barrel serve to further slow the gases of firing, releasing them over a long period of time and avoiding the sharp explosion that occurs when high pressure powder gases are suddenly released to the atmosphere.

The Welrod used a bolt-action design because it was simple, reliable, and quiet. The bolt-action has only the noise of the firing pin hitting the primer, and the bolt can be cycled quietly. While single shots were the norm for the missions the Welrod was used in, the action could be cycled and a new round ready to fire in less than a second.

The Welrod was a "sanitized" weapon, meaning that it had no markings indicating its manufacturer or country of origin; all it was marked with was a serial number and some inscrutable symbols and letters. The Birmingham Small Arms Company confirmed that they manufactured some of the Welrod pistols, but that they put no markings at all on them, so any markings were likely added by the British military after delivery.

This is a replica pistol as the real item, when deactivated is upwards of £2000...The Welrod was used by SOG teams as a prisoner snatch weapon or for silent "removal" of enemy sentries.