Booby Traps FM 5-31 Book Review and Thoughts

The Boobytraps FM 5-31 military manual (pictured to the right) is the definitive guide to booby traps that cannot, and should not, be used by civilians. Booby traps are effective tools in war time, not for home defense. Still, the book is an interesting read for imagining home defense in a post-apocalyptic situation where the rule of law is long gone.

by Logan Misseldine, contributing writer

What are Booby Traps?

The Boobytraps Field Manual 5-31 is a military manual that will teach you not only how to properly use booby traps, but how to detect and disarm them as well. According to the manual, “A booby trap is an explosive charge cunningly contrived to be fired by an unsuspecting person who disturbs an apparently harmless object or performs a presumably safe act.”

Are Booby Traps Legal?

Short answer: Absolutely not! According to US Legal…

If a person sets up such a trap to protect his/her property, he/she will be liable for any injury or death even to an unwanted intruder such as a burglar. It is illegal to set a booby trap on one’s own property to prevent intruders.

If someone is wounded by a booby trap you have set in your home, you will almost certainly be prosecuted. What may have been intended as a way to protect you could end up sending you to jail for many years.

In addition, the danger involved in setting booby traps is very real, both for the enemy, but also for you and any friends or loved ones. Consider, as an example, the case of the Maine man who was killed by his own booby trap.

Let me say it again to be clear: It is illegal to set booby traps in your home. Setting a trap for a potential threat you may or may not even know is coming puts innocent people, even yourself, at unnecessary risk.

Any talk of setting booby traps must be kept in the context of TEOTWAWKI, a desperate last resort in war-time scenarios.

Are Any Booby Traps Legal?

Booby traps are intended to injure or kill an unsuspecting enemy. These are illegal. But you can use as an alarm system, something that immediately lets you know the whereabouts of someone on your property.

Alarms that cause no harm to the individual are not booby traps. An example of this would be a tripwire with tin cans attached that rattle when the wire is pulled. A few other examples include..

FITH OPS Alarm Signaling Device

legal booby trap
OPS Alarm Signaling Device

This device will alert you when trespassers are on your property.

legal boobytrap
Pull String Perimeter Alarms

Pull String Perimeter Alarms

These will not generate the same type of noise as the prior device, but they make a noise nonetheless. They “should” work enough to alert you if someone has entered your home.

Boobytrap Construction

While booby traps can come in an assortment of shapes, sizes, and configurations, most military-grade traps consists of the following:

  • Main Charge
  • Firing Device
  • Standard Base (optional)
  • Detonator

There are other items that can improve a trap or make it more adaptable. War-time examples include a fuse or a booster, which produces a larger concussion than a detonator, increasing the intensity of the explosion and decreasing the likelihood of a misfire.

The booby trap manual illustrates that there are two main types of booby traps used:

  • Improvised: As you can imagine, improvised booby traps are traps made from materials that are generally used for other purposes.
  • Manufactured: These are devices that are made at a factory, usually specifically issued to soldiers. They typically will imitate some object or article that the enemy would find appealing enough to pick up.

Selecting the proper device when placing a trap is a crucial step. While you can adapt any of them to most scenarios, choosing the right one can mean the difference between an accidental discharge, the trap never going off, and effectively creating enemy casualties.

Where to Set Up Boobytraps

The manual illustrates the ideal places to install a trap much better than I can in this article, but the simplest answer to this question is: wherever your target will interact with it.

rifle booby trap
A screen capture from the booby trap manual shows how easily someone could be lured into a deadly trap.

Knowing the Enemy

Before soldiers even lay a booby trap, they need to do their homework. They must determine the paths that an enemy would take, and select the most likely ones to set traps on. They may need to create obstacles to better direct their movements to the trap.

Soldiers have to find the routes their enemies walk, the objects they pick up, and the doors they open. This gives them the best locations for the traps. If they are going to repeatedly use traps to attack an enemy, they must vary the traps used. Enemy forces will catch on, making use of the same trap a useless endeavor. And if they’re able to defuse it and reset it, it could potentially be used in reverse.

Where Soldiers Place Booby Traps Indoors

Buildings, and their surroundings, are very effective places for booby traps. They give a sense of comfort and shelter, which means that they will probably have the most traffic of a particular area. Targeting these locations is also easy as you can hide a device nearly anywhere in a building, including:

  • In Doorways
  • Under Walkways
  • Attached to Windows
  • Inside Furniture

The manual describes how the best placement of an indoor booby trap can be as simple as laying a tripwire in a dark hallway, or installing a pull device on the front door. Soldiers find areas where the enemy will encounter the trap, but also where they won’t see it before it’s too late.

book boobytraps
Another screen capture from the book.

This is one of the best scenarios soldiers use to utilize a delayed detonator, especially if a group of enemies is being funneled into a building. As the first target triggers the trap, it goes off when the most people are within the range of the explosion.

Where Soldiers Place Booby Traps Outdoors

Outdoors is harder for soldiers to work with than indoor locations. There are nearly infinite routes and potential placements that it can be hard to not just set up a minefield and hope for the best. Being resourceful and studying the natural paths and contours shows soldiers the best places to set your booby trap.

They look for the paths that funnel traffic into only one relatively easy route through an area. If there aren’t any natural funnels they might create one. Using natural or man-made materials to block off the easiest routes may work, using anything from disabled vehicles to felled trees.

Disarming a Booby Trap

There are two steps to neutralizing a booby trap:

  • Disarming/replacing safeties in the firing assembly
  • Defusing or separating the firing assembly from the main charge and the detonator.

If it can’t be safely disassembled by hand, the booby trap will have to be set off from a safe distance. It’s always safer to destroy the trap rather than try to disassemble it.

How to Detect a Booby Trap

The manual details that in a normal military scenario, a team of trained technicians and clearance teams would use specific tools and techniques to clear traps. While no one can replace the training and experience gained from being on one of these teams, the manual does explain the basic techniques to safely detecting booby traps.

detecting booby traps
A screen capture from the manual displays moving carefully with a knife if booby traps are suspected.

The cardinal rules for detecting a booby trap are:

  • Be alert and vigilant
  • Move slowly and methodically
  • Look for any unusual marks or objects
  • Don’t move any object before you’ve thoroughly inspected it

Would I Recommend FM 5-31 Booby Trap Manual?

If you want to buy a copy of FM 5-31, there are hundreds of crisp detailed illustrations that help the reader comprehend each concept and instruction. The information is devoid of any fluff.

Do I think preppers need the book? Probably not.

Is it an interesting read just the same? I thought so.

I’m curious, however. What military manuals do you find useful for prepping?


- -