The topic of body armor comes up in discussions often when it comes to self defense or SHTF. Unfortunately, most people who have not served in armed services, law enforcement, or private security have very little understanding of the purpose and the limits of body armor. A vast majority don’t understand the ratings of body armor. I was asked awhile back to do a series on this topic, and I’m finally getting around to it.
In order to cover the topic properly, I felt it best to break it into 3 parts. This first part will the basic explanation of what body armor is, and how it works. To put it simply, body Armor is designed to stop the projectile from penetrating the wearer’s body. It’s primary purpose to prevent the bullet from entering the body cavity and destroying the vital organs and arteries . That’s all it’s intended to do. There are 2 basic ways in which this can be accomplished.
The first is to spread the energy of the bullet by absorbing it over an entire surface area of the vest. This is what materials like Kevlar does. Kevlar is a ballistic thread material which is weaved together and tightly layered. When the bullet hits the Kevlar vest, there is “give” in the material, and that give allows the energy to be transferred across the entirety of the vest. Similar to how a soccer ball is caught by a net of the goal but does not go through the netting. Since the energy is not centrally located at the point of contact, it helps prevent the bullet from entering the body. This type of body armor is known as Soft Body Armor. It’s what commonly worn by street cops and security/bouncers at entertainment venues.
The second way in which body armor can defeat a bullet is with pure strength. Most bullets are made of lead or lead covered with a metal, most of the time it’s “jacketed” by copper. To stop the bullet from going into the body, a plate of steel, or ceramic is placed in the vest instead of Kevlar. The Ceramic Plates will work similarly to Kevlar at a subatomic level. It absorbs the energy of the bullet and spreads it across the plate by fracturing. Because of this behavior, ceramic plates usually can not sustain multiple hits. Steel Plates defeat the bullet by causing the lead bullet to fracture and deform. Steel is stronger than lead. Steel plates are also heavier than ceramic plates. This is referred to as Hard Body Armor.
While there are more complex and newer technologies in development at the military level, Soft Body Armor and Hardened Steel or Ceramic plates are the two most commonly available variations available to the public. Soft Body Armor is intended to stop handgun caliber bullets, and steel or ceramic plates are intended to stop rifle caliber bullets. There is a standard industry rating system to identify which product will be effective for which threat. This is the National Institute of Justice Ratings for Body Armor, or more commonly known as the NIJ rating. Each plate or vest system will be rated and will have a tag indicating the shelf life and the effectiveness level of that particular vest or system. Kevlar degrades over time. Some ceramic plates are not drop resistant. Steel typically does not have a shelf life while sitting on a shelf.
This link will detail the ratings, and the calibers they are intended to defend against.
In part two of this series, I will go into some myths about body armor, the advantages of soft vs hard body armor, and what is available to the public.