“TheCeļotājs”
"Latvia" Former Soviet Union Military Bases
 
Firing Pin Detonators 
 
A firing pin or striker is part of the firing mechanism used in a firearm or explosive device e.g. an M14 landmine or bomb fuze. Firing pins may take many forms, though the types used in landmines, bombs, grenade fuzes or other single-use devices generally have a sharpened point. In contrast, firing pins used in firearms usually have a small, rounded portion designed to strike the primer of a cartridge, detonating the priming compound, which then ignites the propellant "in the case of firearms" or fires the detonator and booster. 
 
Firing Pin vs. Striker
 
         
                            Russian MV-5 Pressure Fuze                                                                     Russian MUV Pull Fuze
 
A firing pin is a lightweight part, which serves to transfer energy from a spring-loaded hammer to the primer, while a striker is usually heavier, and is directly connected to the spring providing the energy to impact the primer. Striker mechanisms are generally simpler, since they combine the functions of hammer and firing pin in one. 
 
         
      
                                      Russsian VPF Pull Fuze                                                                           Russian Type 99 Grenade
 
The firing pin or striker is generally located in the bolt of a repeating firearm. Firearms that do not have bolts, such as revolvers and many types of single-shot actions, generally have a very short firing pin in the frame, or else attached to the hammer itself. These types of firearms are almost never striker fired, as there is insufficient space to house a striker mechanism. Strikers are most commonly found in pistols and bolt action firearms.
 
Firing Pin Construction
 
The typical firing pin is a small rod of steel, with the end that strikes the primer rounded into a hemispherical shape and hardened. The rounded end ensures the primer is indented rather than pierced, as would happen if the firing pin were sharply pointed. Most firing pins have a spring to push them out of contact with the primer, and often will have an integrated passive safety mechanism, such as a block that prevents them from moving forward unless the trigger is depressed, or a transfer bar, also trigger actuated, that must be in place to allow the hammer to depress the firing pin. This safety is in addition to any manually operated safety or safeties that act to block the trigger or hammer.
 
Firearms that use long firing pins, such as pistols, will often use a firing pin that is too short to project when depressed flush by the hammer. This type of firing pin, called an inertial firing pin, must be struck by a full fall of the hammer to provide the momentum to move forward and strike the primer. If the hammer is down, resting on the firing pin, it is very unlikely that a blow to the rear will provide enough energy to the firing pin to detonate the primer. Most variants of the M1911 pistol use this type of firing pin. 
 
Many firing pins are stamped from sheet steel, forming a rectangular cross-section rather than a round one. These will often have a cylindrical section at the front rather than a hemispherical one, and are fairly common in rim fire firearms. Sturm, Ruger, for example, uses sheet metal firing pins in its 10/22 carbine and Mark II pistol.
 
High performance firing pins are often made from lighter materials than steel, such as titanium. The lighter material increases the speed at which the firing pin travels, and reduces the lock time, or the time from trigger pull to the bullet leaving the barrel.
 
Striker Construction
 
Strikers are basically spring-loaded firing pins, generally of a one- or two-piece construction. In the one-piece striker, the striker is turned on a lathe out of a round bar of metal, much larger in diameter than a firing pin, to provide the mass required to detonate the primer. Two-piece strikers generally consist of a firing pin attached to a heavier rear section. in essence a hammer attached to the base of a firing pin. Two-piece strikers are commonly found on bolt action rifles, while single-piece strikers are found on pistols, such as those made by Glock. 
 
Other Uses 
 
              
 
Mechanisms involving firing pins can be used also in other pyrotechnical systems, ranging from hand grenades to chemical oxygen generators.
 
Trip-Wire
 
A trip-wire is a passive triggering mechanism. Typically, a wire or cord is attached to some device for detecting or reacting to physical movement.
 
A trip-wire may be a wire attached to one or more mines, normally bounding mines and the fragmentation type, in order to increase their activation area.. Alternatively, trip-wires are frequently used in booby-traps, whereby a tug on the wire or "release of tension on it" will detonate the explosives.
 
Soldiers sometimes detect the presence of trip-wires by spraying the area with Silly String. It will settle to the ground in areas where there are no wires; if there are any, the string will be suspended in the air but not set them off due to its light weight. It is being used by U.S. troops in Iraq for this purpose.
 
Booby-Trap
 
Booby-trap is a device or setup that is intended to kill, harm or surprise a person, unknowingly triggered by the presence or actions of the victim. As the word trap implies, they often have some form of bait designed to lure the victim towards it. However, in other cases the device is placed on busy roads or is triggered when the victim performs some type of everyday action e.g. opening a door, picking something up or switching something on. Booby-traps should not be confused with mantraps which are designed to catch a person. Lethal booby-traps are often used in warfare, particularly guerrilla warfare, and traps designed to cause injury or pain are also sometimes used by criminals wanting to protect drugs or other illicit property, and by some owners of legal property who wish to protect it from theft. Booby-traps which merely cause discomfort or embarrassment are a popular form of practical joke.
 
Military Booby-Traps
 
A military booby-trap may be used to give away the location of an enemy by triggering a signaling device, or it may be designed to kill or injure a person who activates the trap. Most, but not all, military booby-traps involve explosives.
 
There is no clear division between a booby-trap and conventional, mass produced land mines which are usually hidden under soil, but may be triggered by a tripwire or directional mine designed specifically to work with a tripwire. Other, similar devices include spring-guns and related mechanisms such as the SM-70 directional antipersonnel mine.
 
What distinguishes a booby-trap is that it is contrived to work in an unexpected manner that takes advantage of the victim's ignorance of the mode of operation. It naturally follows that booby-trap designs must be many and varied and for this reason the traps are often at least partially improvised from some item of ordnance such as an artillery shell, grenade, or quantity of high explosives. However, some mines have features specifically designed for incorporation into booby-traps and armies have been equipped with a variety of mass produced triggering mechanisms intended to be incorporated into booby traps in a wide variety of ways.
 
A booby-trap is generally concealed or disguised in some way so that it either cannot be seen or looks harmless. Typically, a booby-trap will be hidden inside, behind or underneath another object.
 
Part of the skill in placing booby-traps lies in exploiting natural human behaviors such as habit, self-preservation, curiosity or acquisitiveness. A common trick is to provide victims with a simple solution to a problem, for example, leaving only one door open in an otherwise secure building, thereby luring them straight toward the firing mechanism. 
 
An example that exploits an instinct for self-preservation was used in the Vietnam War. Spikes known as Punji sticks were hidden in a grassy area. When fired upon, passing soldiers unknowingly take cover in the booby trapped area, throwing themselves down on the spikes.
 
Attractive or interesting objects are frequently used as bait in order to lure victims into triggering the booby-trap. For example, troops could leave behind empty beer bottles and a sealed wooden packing case with "Scotch Whisky" marked on it before leaving an area. The rubble-filled packing case might be resting on top of an M5 or M142 firing device, connected to some blocks of TNT or to some C4 explosive stuffed into the empty fuze pocket of a mortar shell. 
Alternatively, the weight of the packing case might simply be holding down the arming lever of an RGD-5 grenade with a zero-delay fuze fitted and the pin removed. Either way, when the case is moved; the booby-trap detonates, killing or severely injuring anyone in the immediate area. Many different types of bait object can be used e.g. soldiers will be tempted to kick an empty beverage can lying on the ground as they walk past it. However, the beer can "partially filled with sand to add weight" may be resting on top of an M5 pressure-release firing device screwed into a buried M26 grenade.
 
Many purpose-built booby-trap firing devices exist such as the highly versatile M142 universal firing device "identical to the British L5A1 or Australian F1A1", or Yugoslavian UMNOP-1 which allow a variety of different ways of triggering explosives e.g. via trip wire "either pulling it or releasing the tension on it", direct pressure on an object "e.g. standing on it", or pressure release "lift/shift something" etc.
 
Almost any item can be booby-trapped in some way. For example, booby-trapping a flashlight is a classic tactic: a flashlight already contains most of the required components. First of all, the flashlight acts as bait, tempting the victim to pick it up. More importantly, it is easy to conceal a detonator, some explosives, and batteries inside the flashlight casing. A simple electrical circuit is connected to the on/off switch. When the victim attempts to turn the flashlight on to see if it works, the resulting explosion blows their hand or arm off and possibly blinds them. 
 
The only limits to the intricacy of booby-traps are the skill and inventiveness of the people placing them. For example, the "bait object" "e.g. a cash box in a corner of the room" which lures victims into the trap may not in fact be booby-trapped at all. However, the furniture which must be pushed away in order to get to the bait has a wire attached, with an M142 firing device connected to a 155mm artillery shell on the other end of it. 
 
A booby-trap may be of any size. However, as a general rule the size of most explosive booby-traps use between 250g and 1kg of explosive. Since most booby traps are rigged to detonate within a meter of the victim's body, this is adequate to kill or severely wound. 
 
As a rule, booby-traps are planted in any situation where there is a strong likelihood of them being encountered and triggered by the targeted victims. Typically, they are planted in places that people are naturally attracted to or are forced to use. The list of likely placement areas includes: 
  • the only abandoned houses left standing in a village, which may attract enemy soldiers seeking shelter.
  • a door, drawer or cupboard inside a building that someone will open without thinking of what might be connected to it. If a door is locked, this makes people believe there could something valuable behind it so they are more likely to kick it open, with fatal results.
  • vehicles abandoned by the roadside, perhaps with some kind of victim "bait" left on the back seat such as a suitcase or large cardboard box.
  • natural choke-points, such as the only footbridge across a river, which people must use whether they want to or not.
  • important strategic installations such as airfields, railway stations and harbor facilities, all of which the invading forces will want to occupy and use.
  • anything of use or value that people would naturally want to possess or which makes them curious to see what is inside it e.g. a crate of beer, a pistol, a flashlight, discarded army rucksack or even a picture torn out of a pornographic 
  • magazine.
A booby trap does not necessarily incorporate explosives in its construction. Examples include the Punji sticks mentioned above and deadfall traps which employ heavy objects set up to fall on and crush whoever disturbs the trigger mechanism. However, setting non-explosive booby traps is labor-intensive and time-consuming, they are harder to conceal and they are less likely to do serious damage. In contrast, booby traps containing explosives are much more
destructive: they will either kill their victims or severely wound them. 
 
Effects
 
In addition to the obvious ability of booby traps to kill or injure, their presence has other effects. These include the ability to:
  • demoralize soldiers as booby-traps kill or maim comrades
  • keep soldiers continually stressed, suspicious and unable to relax because it is difficult for them to know which areas, buildings or objects are safe
  • slows down troop movement as soldiers are forced to sweep areas to see if there are more booby traps.
  • make soldiers cautious instead of aggressive and confident
  • create no-go areas "real or imagined" after a booby-trap has killed or wounded someone
  • cause a section or platoon to have to stop in order to deal with casualties, thus slowing and delaying those troops
  • create confusion and disorientation as a prelude to an ambush
Booby-traps are indiscriminate weapons; like anti-personnel mines they can harm civilians and other non-combatants "during and after the conflict" who are unaware of their presence. Therefore, it is vitally important for any force which places booby-traps to keep an accurate record of their location so they can be cleared when the conflict is over.
 
Usage throughout History
 
During the Vietnam War, motorcycles were rigged with explosives by the National Liberation Front and abandoned. U.S. soldiers would be tempted to ride the motorcycle and thus trigger the explosives. In addition, NLF soldiers would rig rubber band grenades and place them in huts that US soldiers would likely burn. Another popular booby trap was the "Grenade in a Can", a grenade with the safety pin removed in a container and a string attached, sometimes with the grenade's fuse mechanism modified to give a much shorter delay than the four to seven seconds typical with grenade fuses. The NLF soldiers primarily used these on doors and attached them to tripwires on jungle paths.
 
The CIA and Green Berets countered by booby-trapping the enemy's ammunition supplies, in an operation code-named "Project Eldest Son." The propellant in a rifle or machine-gun cartridge was replaced with high explosive. Upon being fired, the sabotaged round would destroy the gun and kill or injure the shooter. Mortar shells were similarly rigged to explode when dropped down the tube, instead of launching properly. This ammunition was then carefully re-packed to eliminate any evidence of tampering, and planted in enemy munitions dumps by covert insertion teams. A sabotaged round might also be planted in a rifle magazine or machine-gun belt and left on the body of a dead NLF soldier, in anticipation that the deceased's ammo would be picked up and used by his comrades. No more than one sabotaged round would be planted in any case, magazine, or belt of ammunition, to reduce the chances of the enemy finding it no matter how diligently they inspected their supplies. False rumors and forged documents were circulated to make it appear that the Communist Chinese were. 
 
As a rule, most purpose-made military booby-trap firing devices contain some form of spring-loaded firing pin designed to strike a percussion cap connected to a detonator at one end. The detonator is inserted into an explosive charge e.g. C4 or a block of TNT. Triggering the booby-trap "e.g. by pulling on a trip-wire" releases the cocked firing pin which flips forward to strike the percussion cap, firing both it and the attached detonator. The resulting shock-wave from the detonator sets off the main explosive charge.
 
 
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Gallery of Firing Pin Detonators –
 
 
 
Revised: 02/03/2013 – 14:59:03