Differences in Bulletproof Vests
While the NIJ rating system makes purchasing a bulletproof vest much easier than it would be without it, the current testing parameters leave out very important metrics of comparison between different Ballistic Materials as well as individual manufacturer’s design and construction decisions.
The NIJ scale categorizes vests/ballistic plates by their ability to stop fixed, defined threats a limited number of times. It serves only as a pass/fail system, either the plate stopped all the rounds, or it did not, without any consideration as to the serviceability of the vest for future use. While this is useful to see what vests will be able to defeat various threats, it ignores durability, service life, and versatility.
Issues in the System
Ceramic plates can achieve NIJ Level 4, meaning they can stop 30 caliber armor piercing M2 bullets, yet by testing protocol 0101.06, each plate only needs to stop one round. Passing Level IV has no requirement for multi-hit capability, each plate could be rendered useless by that one round and become incapable of stopping even pistol fire and it would still pass Level IV rating. Whereas an AR500 steel plate capable of defeating similar, though lead cored, 30 caliber projectiles, must stop six impacts per plate in order to pass Level III. It is in this rather odd system that exists the possibility that a ballistic plate may pass Level IV requirements, but fail Level III. It is in this over-simplification of ballistic performance into a four level scale that many people get confused or are misled as to the real-world capabilities of the product that they are purchasing. Many opt to spend multiple times more to purchase Level IV Ceramic plates under the logic that IV is better than III, and
The manufacturer also determines the role of the bulletproof vest they produce in how they choose to make it. At its core, most AR-500 steel does not differ greatly in weight, only in compositional strength. While all AR-500 has a Brinell hardness rating of 500, that scale is only based on one test, and does not measure all of the properties and characteristics that determine a plate’s ability to stop rounds. While Hardness is probably the most important, flexibility is also critical. Just like in swords, if the plate is too brittle, the steel can shatter instead of absorbing the impact rendering the plate useless. Hence why AR600 is not nearly as common, in order to achieve the higher hardness rating, the steel becomes too brittle. Manufactures are often quick to cite the “low weight” of their plates, conveniently overlooking the actual dimensions of the strike face itself. Sure, Plate B may be 8 oz. lighter than Plate A, but if they are both made of the same material at the same thickness, then Plate B is simply smaller and therefore offers less protection. Of course, this diversity is good, those wishing to run smaller plates can do so, but having weight be the end-all differentiation between two otherwise similar plates is misleading.
While the NIJ rating of a vest is a good place to start the search for the best bulletproof vest, it should never be the final or only criteria. With the multitude of materials, cuts, and carrier designs, there is a vest out there that is perfect for your needs without breaking the bank. The ballistic protection market has exploded as of late and product diversity is at an all-time high and competition is driving prices down. There has never been a better time to invest in a bulletproof vest.