“Flash-bangs” are a key weapon in the modern special operations forces (SOF) and Special Weapons and Tactics (SWAT) team armory. In hostage rescue/urban tactical situations, they distract and disorient the captors and/or defenders, giving assault teams vital seconds to deal with them before they are able to react. One of the earliest “non-lethal” weapons to be deployed, flash-bangs were invented to deal with a growing paramilitary development in an increasingly violent world: terrorism. The early 1970s were a time of violent leftist direct action across the globe, as a number of disenfranchised groups began to see acts of violence against civilian targets as a viable way of gaining the world’s attention. Initially, these took the form of airline hijackings, but rarely resulted in fatalities. Then came Munich.

In 1972, the Palestinian terrorist group Black September took hostage and killed 11 Israeli athletes and coaches at the Munich Olympic Games. It would take other countries (except Israel) months or years to react and develop a counterterrorism (CT) strategy and capacity. The British Special Air Service (SAS) however, reacted immediately. The morning after the massacre, the commanding officer of the 22nd SAS Regiment tasked his B Squadron with forming an SAS counterterrorism team, officially known as the Counter Revolutionary Warfare Wing (CRW). B Squadron’s immediate mission: Identify potential target types and develop the techniques and technologies this new form of warfare (counterterrorism ) would require.

The CRW’s initial presumed terrorist targets list included embassies, commercial aircraft, oil drilling and production rigs, and various kinds of hostages. B Squadron’s approach was “Chinese Parliament style”; everyone contributing irrespective of rank. They ran through a whole series of scenarios, working out what the terrorists would do, how the SAS CT teams might counter, and how the terrorists could counter the CT teams. In virtually every scenario considered, the critical handful of seconds after entering a siege situation or hostage-filled room was part of this debate. A key conclusion was that the SAS needed something that might distract and disorientate the gunmen, so the assault team could identify and deal with the any enemy gunmen before they could kill the hostages.

The SAS were aware of one such device already in the British army’s inventory: the “Thunderflash,” which, when detonated in a confined area, gave off a loud bang. Thunderflashes had been around for many years, but had evolved little since their introduction. Now, the SAS asked U.K. government engineers to develop a version that looked like a conventional hand grenade, the idea being that if a terrorist saw a grenade come into a room, he would think it was going to explode, and would hesitate, giving the assault team extra vital seconds to enter. The key development came from a scientist of the U.K. government’s top-secret chemical and biological warfare research establishment at Porton Down. The effect of a pyrotechnic “bang” would be magnified, he said, if, milliseconds before the “bang,” the grenade emitted a high-power flash. The result was the G60 stun grenade, today better known as the flash-bang.

The G60 contained a 4.5-gram charge with a mix of magnesium and potassium perchlorate. On detonation it created a blinding flash equivalent to 300,000 candlepower, activating all of the light-sensitive cells in the eye, and making vision impossible for approximately five seconds. In addition, the G60 emits a bang, equivalent to 160 to 180 decibels, which unbalanced and disoriented victims by disrupting the fluid in the inner ear. The grenade itself remains intact upon detonation; it is cylindrical, with the light and noise being emitted through holes down the sides, so there is no shrapnel to harm hostages. One problem of the G60 was the danger of the flash setting fire to flammable objects nearby, but this was considered acceptable given its tactical benefits and capabilities.

No weapon has worth unless it is fully integrated with proper tactics for its usage, and the SAS worked hard to create a new doctrine for CT operations that included the G60. In their “Killing Room” at RAF Hereford, the SAS developed and refined the way they would use flash-bangs in conjunction with close-quarter weapons like the Browning Hi-Power pistol and H&K MP-5 submachine gun. With dummies standing in as terrorist gunmen, but with live hostage roleplayers (SAS volunteers sitting in), live ammunition and flash-bangs were used for the first time. Inside the “Killing House” (and in borrowed aircraft cabins) formal “room clearing” operations were practiced and tactics polished. In the years that followed, the SAS shared their new CT tactics with SOF forces from around the world and got ready to provide advice and support should it be asked for.