Ballistic Shields

Modern Ballistic Shields: A Primer

Today’s ballistic shields can be described very simply as “man-portable hard armor ballistic barriers.” The most common type, which fits the classical definition of the word “shield,” is hand-held or supported by its user’s body. A somewhat less common type is too large and heavy to be used in such a manner, so it is supported by a wheeled trolley.

Ballistic shields are similar to hard body armor plates in their construction and are generally made from a small handful of common ballistic materials:

Fiber-resin composites: Such as Kevlar (para-aramid) fabrics stiffened with phenolic resin or UHMWPE fiber or tape laminates held in place with polyurethane resins.

Ceramics: Including aluminum oxide, silicon carbide, or boron carbide.

Steel: Including MIL-DTL32332, AR550, or other ballistic grades of steel, typically martensitic low alloys.

These materials are often used in combination. A “ceramic armor plate” usually consists of a ceramic layer bonded to a backing layer made of a fiber composite (fiber-reinforced plastic, FRP). The ceramic layer will typically be anywhere from 0.13” thick to 0.4” thick, and the FRP backing layer in the 0.25” to 0.6” thickness range. In this sort of material configuration, the high-hardness ceramic layer serves to break up any incoming bullet core, and the FRP backer absorbs the fragments and residual kinetic energy. Less frequently, a ceramic layer can be used over a ductile metallic backer, or a hard metallic strike-face can be layered over an FRP backer.

Material Selection: In practice, ballistic shield material selection hinges on the answers to two questions: (1) What level of protection is the shield going to offer? (2) What is the target weight? The answer to the first question determines where and when the shield ought to be used, while the answer to the second determines how the shield can be used.

NIJ Specification for Ballistic Shields: The first step in determining the level of protection is to refer to the NIJ specification for ballistic shields, 0108.01. This specification, released in September 1985, has not been updated since because it hasn’t needed updating. 

Levels I through IIIA: Offer protection from handgun threats. Levels I and IIA are now depreciated, and Level II along with Level IIIA are the only commercially available options for shields rated to protect from handgun threats.

Level III: Offers protection from most rifle ball rounds.

Level IV: Offers protection from steel-cored AP threats and all rifle ball rounds, including high-velocity and magnum rifle threats.

Commercially, shields rated to “Level III+” are also commonly encountered. “Level III+” has no clear definition. It should refer to armor that complies with the Level III specification and is also capable of defeating common steel-core ball rounds like M855/SS109 and 7.62x54mmR LPS. In practice, it means whatever the manufacturer’s marketing department wants it to mean.

Weight Considerations: As shields move up the level ranking, they get heavier. Typically, a Level IIIA shield weighs less than half what a Level III shield weighs, which itself is less than half the weight of a Level IV shield. Shields rated to Level III and below are usually made entirely from UHMWPE-based fiber composites—they do not usually make use of ceramic or metallic ballistic materials. Level IV shields must be made either with ceramic armor techniques or from extremely heavy plates of steel nearly ½” thick.

If all shields were 12×12” square, the average Level IIIA shield would weigh about two pounds, including paint, trim, and a lightweight handle. The Level III shield would weigh around 4.2 pounds. The ceramic composite Level IV shield would weigh just north of 8.5 pounds. 

However, shields typically measure much larger than that; the smallest are rarely under 18×24”. Even that “small” 18×24” shield has a surface area three times larger than our one-square-foot hypothetical and four times larger than a 10×12” SAPI-style armor plate. A small IIIA shield can be substantially heavier than a Level IV body armor plate, a small Level III shield weighs about as much as two Level IV body armor plates combined, and virtually all Level IV shields are well over 30 pounds.

For reasons pertaining to weight, the Level IIIA shield is the most common type on the market today. Rifle-rated Level III shields are considerably rarer. Level IV shields are highly specialized, very rare, and typically resemble wheeled barricades.

Shield Geometries: The first ballistic shields were flat rectangles. Up to the early 2000s, shields that weren’t flat rectangles were rare. Today, the flat rectangle is far less common, and curved shields with cutouts and other design flourishes are unremarkable. As methods of shaping and molding UHMWPE composite materials advance, shield design will eventually converge on a small number of optimal forms.

Some would argue that the shield had already been ergonomically “optimized” by the hundred generations of men who fought with them, and that new materials and technologies will simply enable shield designers to take more inspiration from the shield designs of the past. The buckler, for instance, was a small hand-held shield, extremely popular throughout the medieval and renaissance periods. Bucklers were designed to be used with arms outstretched and were very light and mobile. Adept Armor offers a ballistic buckler — the NovaSteel Buckler — designed to be held away from the body. As such, it can protect a significantly larger area than its size would otherwise indicate. Though just 12.2” in diameter, if held properly, at arm’s length, it should offer a much larger area of protection than most armor plates or vests and would protect areas that are typically unarmored, like the neck and face.  Moreover, at just over three pounds, it’s light enough to wear on one’s belt. Made of a ballistic steel alloy, it can double as a compliance or close combat weapon. 

Other possibilities abound. The pavise—a mobile crossbowman’s barrier, complete with a kick-stand—might be another particularly interesting form to draw inspiration from. Interlocking shields, modeled after early shield walls, are another possibility, which could make for modular barriers.

Future Evolution of Ballistic Shields: The shield will continue to evolve in materials—there’s considerable room for improvement with current ballistic materials—and it’s a fair assumption that shields will keep getting lighter and more capable with time, indefinitely. But there are only a handful of ideal shield forms, even in principle, and current materials and processing techniques are allowing them to come to light.