When it comes to body armor, a lot of time is spent talking about stopping bullets. However, very little time is spent talking about the reality of what happens when you get shot while wearing armor plates. Maybe this is a subject that some body armor companies do not like to talk about because they are worried consumers might be scared away purchasing body armor? At Spartan Armor Systems we feel it’s important for anyone who is looking to buy body armor knows what to expect in the absolute worst-case scenario. Blunt force trauma is a reality of body armor and having a good understanding of it will help you determine which type of body armor is ideal for the scenario you are preparing for. Body armor is not going to do you much good if the impact from a round is enough to immobilize and leave you susceptible to additional damage.

What is Blunt Force Trauma?

As the name suggests, blunt force trauma is damage resulting from the impact of a blunt object. This can apply to anything from a baseball bat to fists. The degree of blunt force trauma can vary widely and is relative to the force absorbed. This means the resulting wound could be anything ranging from light bruising, all the way up to broken bones and internal bleeding. As it relates to body armor, blunt force trauma is caused by the force of the bullet impacting the body armor plate. As shown in the diagram below, the kinetic energy of the bullet dissipates beyond the body armor plate. This means that skin tissue and organs on the other side of the body armor plate are going to absorb this shockwave of energy. However, the size of that shockwave can vary based on the inertia of the bullet and the type of body armor plate being worn. The National Institute of Justice (NIJ) has a maximum measurement of deformation allowed. This measurement is called “Backface Signature”, commonly called backface deformation. The maximum allowed backface deformation measurement is 44mm (1.73 inches). This measurement is taken by placing a block of clay behind a body armor plate and then shooting the armor plate, then measuring the depth of the resulting crater in the clay. If you’re shot while wearing body armor, it’s definitely good that the first bullet has been stopped, but what if there are more bullets on the way? The ability to move away from danger is an important consideration when you are looking to buy body armor. This is where you want to place some careful thought into the type of material your body armor is made of.

Which body armor materials limit blunt force trauma?

The more rigid a body armor plate is, the less blunt force trauma you can expect. For example, if you shoot a level III steel core body amor plate with a M80 Ball round, you will not see nearly as much backface deformation as you would with a level III UHMWPE body armor plate or even a level IV ceramic plate for that matter. Each material handles ballistic resistance in a different way. Steel core body armor is by far the most rigid, meaning that the armor itself does not deform when shot. However, UHMWPE and Ceramic materials are more malleable so the back of the armor plate will show a large dimple where a bullet has made impact. Keep in mind that the kinetic energy continues to travel beyond that dimple. This dimple effect is not seen with steel core body armor, such as our Spartan™ Omega™ AR500 or Spartan AR550 products. As the illustration above demonstrates, there is no armor flex in steel core armor compared to ceramic, UHMWPE and soft armor. If you’ve seen videos circulating on social media of flexible rifle rated armor lately, it’s important to consider that they do not test those products against 7.62x51 M80 BALL (probably because the resulting backface deformation would be scary). The more flexible armor is, the more secondary injuries you should expect from blunt force trauma. The diagram below depicts injuries related to blunt force trauma. In minor cases you would expect bruising around the area of impact. In more severe cases, you would see severe bruising in a large area with a puncture where the bullet made impact. Broken bones are also a possibility. Keep in mind that the level of injury sustained is directly related to the caliber of round and the type of body armor worn.