Bulletproof vests and ballistic armors have been in development since the 1500s, but they did not reach their true potential until the modern era. Since the introduction of firearms into warfare, the elite have always been interested in developing armor capable of stopping this firearms. In its first iterations, “bulletproof” armor was simply high quality 16th century battle armor that was sturdy enough to stop the weak firearms of the day. Eventually, bulletproof vest would become both inexpensive and capable of protecting their users against even modern high-powered rifles.
Bulletproof armor and clothing remained the plaything of the social elite for most of its history before the modern period that followed industrialization. Before the availability of synthetic alternatives, silk was woven in multiple layers, sometimes with thin sheets of steels mixed in, to catch pistol rounds. Silk was found to be effective because of its high tensile strength, meaning it can withstand a lot of stress acting toward stretching it without breaking. When individual silk fibers are woven together into silk cloth and then stacked in large bundles, the strength of the individual strands is multiplied giving the vest the ability to stop the black powder pistols of the day. The addition of thin steel plates into the layers of silk only added to this early armor’s effectiveness.
The Modern Era
With the invention of Kevlar, the bulletproof vest market exploded. Kevlar has an extremely high tensile strength for its density, meaning it is extremely strong for its weight. Kevlar when it is manufactured is actually just small individual strands of material. On their own these small fibers are very weak, but when woven together in deep interconnected layers their collective strength is enough to stop pistol fire. Because of their light weight, Soft Kevlar vests became the standard for police and military units throughout the world. Eventually Kevlar became easy enough to produce that it proliferated the market. Soft Kevlar vests are what most people think of when they hear bulletproof vest, but Kevlar is no longer the best material available. With advances in steel hardening, less steel is required to make a vest bulletproof. As a result, bulletproof vests made with steel ballistic plates are now light enough to wear while offering superior protection to Kevlar.
Steel in Ballistic Armor
Traditionally, older milder forms of steel were vulnerable to high-speed rifle cartridges when made light enough to wear. Thus, steel armor was relegated to vehicle use as a bulletproofing material. Mild steel and Kevlar offer essentially the same ballistic protection, but Kevlar is significantly lighter and more flexible. Yet, this balance has shifted. Now thin plates of extremely hard steel are able to stop the vast majority of rifle rounds, a feat impossible for a Kevlar vest to replicate. Ballistically hardened steel plates (typically rated at AR-500 or a similar hardness) are tough enough to be used as pistol range targets. Pistols have little to no effect on the integrity of these plates, and it takes a very fast rifle round to cause even minor damage and a very powerful round to ever penetrate all the way through. AR-500 steel plates will handle magazine after magazine of the most common and deadly rifles in the world like the AK-47/74 and AR15/10 variants.
The future of Bulletproof Vests more than likely lies in the development of Graphene, a newly discovered super-material that has a tensile strength to weight ratio higher than Kevlar or even Carbon Fiber. As of now though, and for the foreseeable future, graphene’s utilization is restricted due to its inability to be produced in quantities greater than a few grams. Until it becomes commercially viable and battle-tested, the time proven humble hardened steel plate will continue to be the best ballistic protection available.