This short-barreled Mark IV 22/45 was whisper-quiet, even with...
If you spotted a Welrod for the first time, you might not realize what it is. In disassembled form, it resembles a piece of industrial equipment, the sort of thing you might find in an obscure corner of the hardware store next to caulk dispensers or hot glue guns. In fact, it was nicknamed the “bicycle pump” by those who used it. It also has no easily-identifiable markings or symbols on its plain metal body.
Howewer, when its 8-round magazine is inserted to form a pistol grip, the Welrod's purpose becomes more apparent. This historically-significant weapon has a very specific purpose: silent use behind enemy lines. Forgotten Weapons recently posted a video analysis of the Welrod Mk IIA, including hands-on disassembly of a surviving example, and and in-depth description of its functionality:
The Welrod was developed in the early 1940s by Special Operations Executive (SOE), a British military organization which coordinated espionage, sabotage, and reconnaissance missions in occupied Europe during World War II. British SOE (along with American OSS and European resistance forces) needed a weapon which could be distributed, concealed, and fired without drawing attention. The pistol's strange appearance accomplished the first two goals, but silent operation was essential to meet the third requirement.
A 12-inch by 1.25-inch cylinder forms the body of the gun, and houses a ventilated barrel and an integrated suppressor. The Welrod fires a sub-sonic .32 ACP cartridge, and is operated with a manual bolt action, further reducing the gun's sound signature.
All of these features bring the sound of a shot to approximately 73 decibels. That's about as loud as the normal background noise of traffic on a city street. While it's not technically silent, it's extremely quiet even by modern suppressed gun standards, and was revolutionary for its time. The rubber wipes inside the suppressor only lasted for about a dozen shots, after which they lost effectiveness, so the shooter needed to make every shot count.
Above: Cross-sectioned photo of a Welrod MkIIA courtesy of TimeLapse.dk (© Anders Thygesen, provided with permission)
Although the secretive nature of this gun makes tracking its use difficult, reports indicate it was used in the Korean War, the Vietnam War, the 1982 Falklands War, and the Troubles in Northern Ireland, among other modern conflicts. Some say it was even fielded by SAS members during Operation Desert Storm, and that an updated version may be in use to this day.