Body Armor Buying Guide
Basic Body Armor Buying and Design Guide
Author: W. Gilliam, Founder, Gilliam Arms
info@gilliamarms.com
This guide contains many of the issues that I’ve addressed in previous videos and blog posts.
Whether you purchase armor from Gilliam Arms or not, we want you to be well-informed about proper testing, and the selection of materials and materials combinations available to meet your goals.
This guide is meant to educate from a layman’s perspective and is more focused on ceramic armor plates. For additional, more technical questions, please contact us at info@gilliamarms.com.
Please see Appendix A for a list of terminology. It may be helpful to review the Appendix prior to reading this guide.
Unlike other “guides” which attempt to drive users toward specific manufacturers, this reference attempts to provide the reader with the knowledge to search for and select the proper armor product among qualified armor builders and manufacturers. The objectivity of other guides and buying advice prevalent on social media wanes with affiliate links and other associations.
This guide uses the terms “builder” and “manufacturer” interchangeably. Armor manufacturing is a process of expert assembly (building). Manufacturers can be large companies with tens of thousands of square feet, or small specialty shops with just a few employees. Both can produce quality armor.
Nothing in this guide should be construed as a specific recommendation for your own protection. Every decision is personal and the outcomes associated with your choice are yours alone. We are not liable for any consequences resulting from your selection of armor.
This guide will be updated to correct errors and periodically to add new information.
About the Author
My experience with body armor is extensive, but I learn something new from everyone. I certainly do not have all of the answers - but, I do have enough experience to start sharing “good” information. I served as an inner-city police officer for five years and began building armor over twenty years ago. Ceramic armor became my focus in 2014. I have built thousands of armor plates with various ceramic, polyethylene and adhesive materials. Much of what I write here are the results of lessons learned through the years.
Some manufacturers will not disclose some of the information in this guide. I feel that it is urgent and relative to disseminate this information on a wide scale.
I do not use armor manufacturer names in this guide. The topics of discussion can be linked to manufacturers as the reader sees fit. The goal of this guide is not to point out specific brand names for criticism. The purpose is to give the reader some insight into what is relevant from a purchasing decision.
Social media is chock full of spam and brand disciples pushing certain armor manufacturers. Sometimes this becomes a toxic environment, devoid of useful counter-presence. These sites often neglect to include much of the information in this guide.
What I write here is from my own experience and may differ substantially from others in the armor industry. These are only my opinions and may not be true in all cases. I have attempted to discuss the below in a depth necessary to assist with consumer decision making and not serve as a scientific paper.
References
National Institute of Justice Ballistic Resistance of Body Armor NIJ Standard 0101.07
The bird’s eye view of the armor landscape
The National Institute of Justice (NIJ) provides oversight of the certified body armor standard and associated testing programs. For more information about the NIJ, please read here.
Body armor on the US market falls into two broad groups: NIJ certified armor and non-certified armor. Certified armor is the gold standard — but there is also a great deal of strong, well-built non-certified armor on the market. The key is this: if you are not going to buy certified armor, you need to buy from a company that is extremely transparent and backs its products with NIJ-accredited lab testing data. Let’s look at both paths honestly (this is an important section).
NIJ certified armor
NIJ certified armor will have a “mark” on the ballistic tag (see below).
Image 1: The NIJ mark.
Only armor using this specific mark is NIJ certified. You will notice armor product descriptions that read something like one or more of the following:
Built to NIJ standards.
Built to NIJ 0101.07 standards.
Built to NIJ RF1, RF2 or RF3 standards.
Tested by an NIJ certified laboratory.
You may even see a “stamp” or “ribbon” on the product that indicates something like one of the above phrases.
None of this means that the armor is NIJ certified and listed on the NIJ Compliant Products List (CPL).
What does NIJ certified armor mean? The first step (after an involved application process) that NIJ certified armor endures is an initial type test involving various mechanical, temperature conditioning and ballistics testing.
The initial type testing is supervised by the National Institute of Justice (NIJ) and is performed onsite at an NIJ certified ballistics laboratory. The initial type test puts the armor through high and low temperature conditioning and cycling, submersion testing, drop testing, label testing (solvent and friction), ballistic perforation back face testing and ballistic limit testing. In other words, the armor is tested to function in all sorts of temperature conditions and rough handling after which must still perform without any complete penetrations of the armor. The vast majority of the shots must also register below 44mm of back face deformation (BFD).
BFD is basically a measure of ballistic energy moving through the armor and is eventually directed into the backing material. This is often measured in laboratories with calipers after shooting a representative sample while strapped to conditioned clay blocks. To put it simply, when the armor is tested it cannot penetrate the armor panel and it can only make a 44mm max dimple in the clay block behind the armor. An example of this process is seen in the video below.
Video 1: The general ballistics testing process (Perforation Back Face Deformation Testing).
The NIJ certified process then requires one plate to be sequestered as a sample and all future built armor of that model must be identically constructed.
The manufacturer must then undergo a facility inspection, further sampling and then enrollment into a follow-up inspection and testing program (called FIT). The FIT program requires random sampling of the armor and facility inspections at regular intervals.
NIJ certified armor is the cream of the crop for production line (assembly line) type armor. It is the pinnacle of armor products designed to show reliability, consistency and proof of performance. Most people should try to purchase NIJ certified 0101.07 armor that is on the Compliant Product List (CPL). It is the gold standard, full stop. NIJ certified armor is superior because it introduces standardization, objectivity and testing.
Non-certified armor
Even so, certification is not the only path to a trustworthy plate. There are instances when companies choose not to produce NIJ certified armor. Some of these reasons are:
- Manufacturing of custom armor.
- Sales volume cannot support NIJ certification testing costs ($25,000 - $60,000 per model with materials costs included).
- When manufacturers are underbuilding armor without adequate drop protection, adhesive strength or materials layering that can resist crown shots and other stringent NIJ-related testing requirements.
- Resellers “flip” imported armor manufactured overseas to U.S. consumers.
There is nothing inherently “wrong” with #1, #2, or #4 as long as the armor is properly constructed and quality systems exist for verifying workmanship and effectiveness.
The manufacture of custom armor requires changes to the layup on almost every armor product produced. This means that custom armor cannot be included in the NIJ certified armor program or listed on the CPL since all armor must be identical in materials layup and production process. Custom armor can still be produced using methods that meet or exceed NIJ requirements.
The danger in the non-certified space isn’t the missing certificate; it’s the missing proof. The same freedom that lets an honest maker build a certifiable custom plate also lets a dishonest one cut corners no customer will ever see — thinner ceramic, a skimpy backer, no real drop protection, no crown-shot testing — and never answer for it. Some “reputable” manufacturers build and sell armor that cannot pass NIJ certified (long-term, repeatable) drop testing. This is done without informing the consumer… and this opens up an unmitigated risk for the wearer.
NIJ initial type testing requires that 25% of all shots be on the crown (apex) of the armor along its highest point. Most manufacturers will not test the crown specifically on underbuilt armor and especially will not show historical testing on crown shots due to poor performance. Instead of building an armor plate that can withstand recurring NIJ-like drop tests and crown shots, they opt to shave 5-6 ounces off the plate weight to enhance marketability.
The image below shows the crown of a multi-curve armor plate (red circle). The areas depicted by green circles are often shot in test reports and represent areas of higher ballistic resistance. For a true indication of armor strength, the crown of the armor must be tested.
Image 2: Showing the crown of a multi-curve armor plate with red circle.
Other times, large quantity orders are placed with overseas suppliers, assembled overseas and imported into the United States for reselling purposes. When most of this armor arrives, it is already assembled - restricting some of the post-manufacturing quality control that resellers can perform. When armor like this is offered for sale in the USA, it is not possible to certify it under the NIJ program (due to NIJ rules).
So the right question is never simply “is it certified?” It is can this maker prove it works? If you are not buying certified armor, buy from a company that is extremely transparent and stands behind its products with NIJ-accredited lab testing data — one that tests frequently, publishes real reports, shows crown shots and drop testing, and will take your phone call. Gilliam Arms is built around exactly that standard. A maker who can’t or won’t prove it should lose your business, no matter what marks are on the tag.
Many of our products significantly outperform certified armor models and the performance proof is in the NIJ lab ballistics reports themselves for customers to evaluate.
Important aspects of ballistic testing
Understanding ballistics testing is absolutely prerequisite to your body armor decision making process. Understanding what is in and what should be in ballistics testing reports is absolutely paramount to your safety. It is also urgent that you understand practices that some resellers and manufacturers engage in to obscure an armor’s true performance.
Must have information in a NIJ-certified lab report includes:
1. The standard being tested against
Preferably NIJ 0101.07, the latest standard, which requires at least 25% of the certifying shots on the armor crown.
2. Date
Establishes a test within a series on the same model, showing reliability and redundancy in design.
3. Manufacturer’s name
Is the manufacturer reputable and transparent with social media and testing reports? Is the name in the report representative of the company you are purchasing from?
4. Armor model number
Limits the reseller from substituting one report for another. For transparency, use the actual commercial model number.
5. Armor specifics (weight, shape, size)
A BFD measurement is typically lower on a larger plate than a smaller one. Remember the BFD on a lighter cut will typically be higher than on the larger, heavier armor.
6. Mechanical (drop) and submersion testing
You should see this at least once per model. Submersion testing guards against crude techniques using liquid adhesives and caulk not suitable for moist conditions. If you only see one example, ask what design elements prevent drop damage.
7. Threat type (M855, M193, .30 M2 AP etc.)
Armor designed for one threat may not stop another. If buying by NIJ levels, you are buying against protection categories (HG1, HG2, RF1, RF2, RF3). To stop 1-3 projectiles, a Special Rifle Threat (SRT) plate could be appropriate.
8. Clay temperature and steel ball drop measurements (19mm nominal +/- 2mm)
Higher temperatures and higher clay validation drops increase BFD by up to 4-6mm. Clay that is too cool will induce a complete penetration, which is the reason for the 19mm +/- 2mm range.
9. Shot number
A manufacturer may be testing something specific and not need maximum endurance. For RF3 armor, shot count counts only when shots are in the right locations. Always request at least one report with a crown shot.
10. Angle (obliquity)
The 6-shot RF3 pattern shows capabilities at 0° and 30°, with the crown shot last. Angled shots are generally easier to resist because there is more material between the projectile and the wear face.
11. Velocity
The NIJ has standards for velocities associated with all ballistic threats. Cross-reference the report velocities against NIJ 0123.00.
12. Measured Back Face Deformation (BFD)
The general requirement is BFD (for most shots) at or below 44mm. For a ceramic composite with higher BFD but little PE ply penetration, it can be beneficial to use foam on the wear face to lower BFD.
13. Amount of penetration (complete penetration = failure or partial penetration = success)
Penetrations are now either partial penetrations (stops) or complete penetrations (failures).
14. Specific shot location on the armor
The crown is the weakest part of the armor. An RF3 plate is considered very strong if it can withstand 2 or more crown shots 3” apart. Be wary of underbuilt, super-thin armor without demonstrated crown testing.
A GTS ballistics report is shown below that contains all of the required elements of a proper test report.
Image 3: GTS Model 1023 ceramic mosaic armor resisting 6 shots of .30 M2AP including the last shot on the crown of the armor. The NIJ 6-shot 0101.07 initial type testing pattern shown. Armor was drop tested and submerged in accordance with NIJ 0101.07 protocols.
Make sure you have test reports for any armor you’re considering. For hard armor, make absolutely certain that you have the 14 elements above and that you have drop testing, submersion and at least one crown shot.
Which ballistic threats do you want to resist? In other words, what do I need?
Now that we have discussed the importance of ballistic testing, let’s talk about selecting the right protection level. The tables below include the most recent protection categories (HG = handgun, RF = rifle) and associated threats, taken directly from the NIJ 0123.00 Standard Protection Levels.
Table 1: NIJ HG1 and NIJ HG2 Ballistic Protection Levels and Associated Test Threats and Reference Velocities (handgun threats).
Table 2: NIJ RF1, NIJ RF2, and NIJ RF3 Ballistic Protection Levels and Associated Test Threats and Reference Velocities (rifle threats).
If you only wish to stop handgun projectiles at Table 1 velocities, you can opt for a soft or hard panel, normally made of aramid or UHMWPE. Two things to point out: most bullet resistant products are called “bulletproof” but are not; and PE is susceptible to elevated heat, so well-designed PE panels should have 3-5 plies of aramid on the strike face side.
Video 2: Example of high performance aramid material used in ballistic vests (handgun).
Make sure you are either buying NIJ certified armor (0101.07 is the latest) or well-tested armor with a complete testing history supported by NIJ-accredited lab reports. The bottom line is that you have to determine for yourself which ballistic threats you want to resist. Here are some examples:
A traffic officer on a rotating inner-city shift believes HG2 is perfect for most circumstances, but may get a call to back up a robbery or domestic violence call. She chooses an RF2 ceramic plate capable of stopping HG2 and RF2.
A security officer inside a concert venue screens guests with AI technology or a metal detector. Due to elevated pre-screening, he chooses an HG2 panel because the rifle-threat probability is low.
A SWAT officer on a warrant team knows he will face rifle threats and wants maximum multi-hit protection. He chooses an edge-to-edge mosaic ceramic tile array in single-curve.
An inner-city patrol officer once caught a person with M993 ammunition (tungsten core). He buys a substantial RF3 silicon carbide, TiB2 plate strong enough to resist M993.
Each choice comes with thickness and weight “penalties.” It is becoming more common for manufacturers to offer Special Rifle Threat (SRT) plates — uncertified plates that rely on test reports to prove the number and type of projectiles stopped. As most encounters involve a single rifle shot, SRT plates could fit consumer needs. Make sure you have a crown shot and demonstrated drop protection that is certifiable in design.
If seeking rifle level protection, consider the sheer number of M855 ammo out there. I would consider it sound judgement to always be in a position to resist this projectile. 100% PE plates are generally a “no go” in my book because of their vulnerability to these steel penetrators (and high velocity M193).
RF2 and RF3 armor limitations
These categories have notable limitations, particularly when facing advanced ammunition such as tungsten core projectiles. It is not common to encounter tungsten outside of the RF2/RF3 categories, but it is possible, as these rounds are available through online marketplaces.
RF2 Limitations: RF2 defeats common intermediate rifle rounds — 7.62x51mm M80, 7.62x39mm MSC, 5.56x45mm M193, and notably 5.56x45mm M855 “green tip.” However, RF2 is not rated for true armor-piercing rounds such as 5.56x45mm M995 or 7.62x51mm M993 tungsten carbide core. These concentrate energy on a small area, enabling penetration of typical RF2 strike faces.
RF3 Limitations: RF3 is the highest rifle protection in 0101.07, required to stop .30-06 M2 AP plus all RF2 threats. Nonetheless, RF3 falls short against tungsten core specialty ammunition exceeding the M2 AP’s penetration profile, such as M995 or the 7.62mm M993. For such threats, seek well-designed silicon carbide ceramic armor built and tested specifically against them.
A note about steel plates
A “no go” in my book are steel armor plates. I have shot steel many times with hunting rounds and the anti-fragmentation coating separates after one or two shots. Steel is very heavy and will not stop the same threats ceramic can. I do not recommend steel and would never wear it. In over two decades in the armor business, I do not believe there is any more effective rifle protection than a well-designed composite (ceramic and PE) armor plate.
The discussion will now focus on hard armor at the RF1, RF2 and RF3 protection categories. The type of ceramic influences armor thickness, weight, performance, and price.
Ceramic materials: aluminum oxide (alumina)
Alumina is the most common type of ceramic used in ceramic body armor plates. It’s much lighter than steel and is hard enough to stop most projectiles you would find on the street. It is also the most affordable type of ballistic ceramic and offers manufacturers significant design flexibility due to the purity levels available.
As a builder, I prefer alumina over harder materials for multiple hit performance. Alumina is not as brittle as silicon carbide and boron carbide and therefore tends to shatter less. There are trade-offs — harder ceramics can potentially resist higher velocity / harder projectiles — but for materials layups designed to meet NIJ RF1, RF2 and RF3 standards, alumina is hard to beat.
One important note about alumina is that a substantial amount of ballistic alumina manufactured in the USA is sold at the 90% purity level. Lower purity levels are less dense (less effective) and are lighter as a result. Outside the United States, there are finished ballistic ceramics offering higher quality alumina ranging from 95%-99.7% purity, available in the USA at higher costs and significant lead times. Any source should be vetted and entered into a quality control program that verifies the ballistic effectiveness of the ceramic.
Quality of materials must be established by the manufacturer and normally includes acceptance inspections, quality reports from the component manufacturer, a process of continuous improvement, hazard identification and mitigation, field testing at regular intervals and NIJ certified lab testing.
High quality alumina ceramic is often in the form of monolithic (single piece) shapes, versus smaller individual tile used to create an armor pattern. The smaller individual tile are often referred to as a mosaic design or ceramic tile array.
Image 4: A monolithic piece of ceramic tile used in the production of composite ceramic armor.
Image 5: Ceramic tile array made from 50mm individual pieces.
On a related note, even though some of the big names in body armor claim “100% Made in USA,” the reality is that many of the most important components are imported. This is not a problem from a quality perspective since the ceramic and the common adhesives are of high quality.
To comply with the Federal Trade Commission’s (FTC) Made in America Standard, companies are supposed to qualify their Made in USA claims when a significant component originates from outside the USA. Ceramic and adhesives are integral parts of composite ceramic armor systems and foreign-sourced versions should include a qualifying statement. Made in the USA with Italian ballistic tile would be one proper claim — but it is rare to see compliance with the FTC Standard. You can read about the requirements for Made in USA claims here.
Alumina ballistic ceramic weight
The manufacturer has a lot of room to design armor with alumina because the available purity levels have a significant impact on density (weight). The image below shows the density of various purity levels associated with a US-based supplier.
Image 6: Alumina density for various purity levels.
To summarize: P90 (90%) alumina has a density of 3.6 g/cm³. P99 (99%) alumina has a density of 3.94 g/cm³. 99.7% alumina has a density of about 3.97 g/cm³. Assuming a 10” x 12” (120 sq in) panel at 10mm thickness, the 90% alumina strike face would weigh 6.14 pounds and the 99.7% tile would weigh 6.78 pounds. The same sized 99.7% alumina tile is .63 pounds heavier than the 90% tile.
Some manufacturers choose 90% alumina in substantial thickness and then choose a backer that accommodates the reduced ballistic effectiveness. This is fine as long as the armor system works and there is an even distribution of alumina across the piece. The problem arises when the distribution is not consistent across lower purity levels, resulting in unpredictable performance. Higher purity increases predictable performance, reliability and distribution — at higher weight and more expense.
This highlights one of the major differences between manufacturers that often remains unnoticed. Well-designed redundancies in armor are often hidden until highlighted by failures in inferior materials. Would you rather purchase a multi-curve 6.9 pound RF3 plate with a 90% alumina tile, or an alternative with a 99.7% alumina strike face that weighs 7.4 pounds? Keep in mind that the vast majority of armor builders will never tell you these things… even when asked.
As alumina is the heaviest of common ballistic ceramics, small changes in plate size can have a tremendous impact on total weight. Many suppliers manufacture a “10” x 12” armor plate” but use a 9.75” x 11.75” strike face, then add edge padding. When comparing plates, small changes in ceramic strike face size can have a significant impact on overall weight. Don’t automatically discount a heavier plate until you find out the total size of the ceramic strike face and its purity level.
Some companies build retracted strike face armor, usually from mosaic tile arrays, 10” x 12” in total size. But the plate area is not entirely ceramic since there is a 1” EVA foam edge around the perimeter. Almost none of this is ever disclosed. Almost all of the 6 - 6.2 pound RF3 alumina armor on the market is built this way — the ceramic is only 8” x 10”, with 1” foam all the way around (see image below).
Image 7: Typical ceramic coverage areas on a composite ceramic armor plate.
Alumina ceramic armor plates built with retracted strike faces are two pounds lighter than their edge-to-edge counterparts. Edge-to-edge means the ceramic strike face extends across the entire backing plate with no foam along the perimeter. Even though retracted strike face armor is two pounds lighter, you have reduced rifle protection across the surface due to the retracted amount of ceramic.
Image 8: Retracted strike face mosaic armor. Did you know your “light” armor had 1” of foam?
Are retracted strike faces acceptable if disclosed? I think so… as long as it is clearly explained and the plate backing material has been tested at the HG2 level. Well-tested retracted armor can be thought of as a hybrid plate: rifle protection in the center and handgun protection along 1” of the perimeter. I usually recommend edge-to-edge unless there is a specific need to do otherwise. Just remember that your alumina 6.2 pound plate is light because of less ceramic.
Alumina armor plate design
In general, you may have three types of armor plate designs (assume 10” x 12” nominal sizing):
- An armor plate that relies on a heavier, stronger ceramic strike face and thinner backing material.
- A balanced approach.
- Armor that relies on a thinner ceramic strike face and more substantial backing material.
As a consumer it is very important to understand which of the three categories your potential plate is a member of. This will heavily influence performance.
#1: This armor is designed to stop two heavy caliber crown shots, and continued effectiveness depends on retention of the ceramic strike face. Pros: Can take a heavy caliber punch, possibly above its rating. Cons: Once the ceramic is damaged, the backing plate will be too thin to resist most rifle-rated threats. Usually heavier plates (8 pounds or so in alumina).
#2: Uses “standard” industry layups — generally about 10mm of alumina and 12mm of PE for a balanced approach with some multi-hit. Pros: Generally more multi-hit than #1. Cons: Still cannot resist most rifle-rated threats with the backer alone. Can weigh in the 7.5 pound range (alumina).
#3: Uses a thinner ceramic strike face and more robust backing that enhances multiple hit capabilities, especially with lead ball. Pros: lightest of the three. The armor can stop one crown shot and up to two additional projectiles at the most powerful caliber in its NIJ 0123.00 category and still retain enough backing to resist repeated common rounds (depending on design). Cons: Cannot generally stop projectiles with diameters greater than the thickness of the ceramic strike face. Usually thicker than the other two.
Which layup is best?
It depends on your situation. I normally prefer #3 because it addresses the primary weakness of ceramic armor. Once the ceramic strike face is compromised, ceramic armor quickly becomes vulnerable. When built in accordance with #1 and #2, follow-on projectiles in the same vicinity are likely to pass through.
Design enhancements can limit susceptibility to grouped shots by including a substantial PE backing plate. Through test data in our BALLISTIQ database — including recent GARMS 1 and Helion testing — we can see that around 13-14mm of quality PE begins to resist RF1-class threats on its own. As a result, you are already in an advantageous position running an RF2 or RF3 plate with a robust PE backer from a multiple hit standpoint. No matter what happens on the first shot, if you encounter common rounds the backer will aid in multiple hit effectiveness.
If you add a quality ceramic strike face on top of that backer and include a substantial crack arrestor, you can stop more powerful RF2 projectiles and the RF3 threat. Even with damaged ceramic, the solo backer is there to resist common threats found on the street.
Another advantage is that the embedded ceramic core of layup #3 provides embedding of ceramic shards into the backer at the shot location. This creates more ballistic resistance than the PE alone, further heightening the likelihood that follow-on shots will be stopped.
Image 9: The three working layers of a robust composite plate. After the ceramic is compromised, a redundant PE backer continues to resist common rounds on its own.
Disclaimer: This is not a catch-all fix for ceramic armor vulnerabilities and will not always work as described for some calibers and specialty ammunition.
I was a pilot for over three decades and remain a current CFII and Airline Transport Pilot. In aviation safety, we always try to design in as many system safety advantages as possible. If everything goes wrong, the system is designed to give you the “best chance” at survival. In this case, layup #3 is the “best chance” opportunity as related to body armor design.
Ceramic strike face monolithics, mosaics and hex shapes
There are several types of strike face configurations: monolithic, mosaic (ceramic tile array), and hexagonal.
Since monolithic shapes are one piece of ballistic ceramic, they are a single shape with exact dimensions and are inarguably the most common type used in modern armor. Having one piece reduces the potential for assembly error where gaps between tiles could exist. Monolithic ceramic is very effective against single shots and is ideal for RF3 armor design where the goal is to certify against a single shot of .30 M2AP. Monolithic forms generally have lower BFD on shot one and are more comfortable. They do not lend themselves to complex custom work, and they experience larger “spall circles” on the reverse side (at times up to 6”), reducing effectiveness for multiple hits within 3” of the entry point.
Video 3: Some differences between mosaic and monolithic armor.
Incoming projectiles create unpredictable cracking across a monolithic form compared to mosaics, which have pre-determined boundaries that act as engineered break points. A monolithic plate is more predictable on shot one than a mosaic but less predictable on all other shots.
Alumina ceramic tile arrays (mosaics), when constructed properly in a 50mm size, are simply the most effective multiple hit armor on the market. They are normally deployed as single curve armor and are quite useful for custom building. Mosaics are labor intensive and prone to assembly errors — the pattern can slide open and gaps emerge as the tile cure, so a quality control system must be deployed. Mosaics must be overbuilt: each piece is only 50mm x 50mm, focusing energy into a small area and requiring more substantial backing. As a result, edge-to-edge mosaic armor is predictably thicker and heavier than monolithic.
Some present the idea that the seams between tile represent vulnerable points. In over 20 years of testing, I have never seen a projectile pass through as a result of hitting a mosaic seam line. The size of the tile has more influence on performance than the seam does. After a monolithic plate is hit, numerous unpredictable cracks open up — some that cannot be seen — so every hit after shot one would be more of a risk than the tight seam lines on a well-built mosaic.
The use of hex tile exacerbates the tile size versus ballistic energy problem and requires even more substantial backing. A practical approach for multi-curve is to use 50mm tile in the lower 2/3 of the plate and hex above.
Comparing alumina, silicon carbide, and boron carbide
Alumina (Al₂O₃)
Widely used for affordability and availability. Relatively heavy, but its lower cost makes it practical at scale. Its hardness (around 14-15 GPa Vickers) lets it shatter or deform incoming projectiles. The trade-off is higher density and weight.
Silicon Carbide (SiC)
At about 3.2 g/cm³, SiC plates are significantly lighter than alumina. Its hardness (20-25 GPa) and high fracture toughness enable it to withstand some tungsten core rounds. It is more expensive to produce. Adding titanium diboride (TiB₂) as a reinforcing phase enhances hardness and fracture toughness without significantly increasing weight. Because SiC focuses energy into a more confined area of the backer, foam is often needed on the wear face to keep BFD under 44mm — so lighter, stronger SiC armor is routinely on par with the thickness of alumina armor.
Recommendation: If you are actively seeking to resist tungsten, SiC should be your choice. I have experienced M995 being stopped by alumina armor in adequate thickness. M993 should be stopped by SiC or a boron hybrid.
Boron Carbide (B₄C)
Among the hardest materials known (Vickers hardness ~30-35 GPa) and remarkably light at about 2.5 g/cm³ — lighter than both alumina and SiC. Its brittleness can lead to excessive cracking, so silicon carbide is often blended in to improve toughness and multi-hit capability. The B₄C-SiC composite can defeat high-velocity, armor-piercing projectiles that might otherwise penetrate pure B₄C plates, but the high cost reserves it for high-priority applications.
Crack arrestors for ceramic armor plates
Crack arrestors are one of the most misunderstood and underutilized features of ceramic armor design. They are strike face treatments that hold the ceramic together so undamaged areas can continue providing ballistic resistance.
Ceramic has a key disadvantage: once a bullet strikes, the damaged ceramic has accomplished its purpose. If the fragments escape via ejection from the strike face, that ejection sends ballistic energy back out through the entry point, creating ancillary damage to surrounding tile. To address this, two strategies can be deployed: a more robust polyethylene backing plate (discussed above), and a crack arrestor that holds the ceramic together.
Image 10: Carbon fiber and aramid fiber interweave acting as crack arrestors (green pieces).
Crack arrestors also help protect against rough handling. NIJ 0101.07 requires that armor plates be dropped from 48” onto a concrete slab while ten pounds of clay is strapped to the wear face, prior to ballistics testing. Various manufacturers simply place a 4-6mm foam pad in front of the raw ceramic. This is not adequate as a crack arresting layer — the layer must be laterally strong, capable of resisting back pressure, and bonded to the ceramic itself. Low fragmentation armor utilizing robust crack arrestors will experience higher BFD when tested (normally 3-6mm at RF3) due to trapping energy within the plate. The only way to know whether crack arrestors are used in your armor is to ask your manufacturer or review disclosed product data.
The idea of “at least one” certified plate
There is a general belief that it’s acceptable to purchase non-NIJ certified armor as long as the company has “at least one” NIJ certified plate. That is not necessarily the case. It is acceptable to purchase non-certified armor from companies that are transparent, test frequently, and have designs that align with industry standards — but there are numerous things resellers or manufacturers can do to disguise true quality:
- Failing to design armor that can withstand NIJ drop testing.
- Reducing redundancies by lowering ceramic purity levels (to save weight).
- Thinning the PE backing to minimal levels.
- Utilizing retracted ceramic strike faces and failing to notify consumers.
- Making improper Made in USA claims.
- Using ballistic test reports that do not belong to the entity involved.
- Using ballistic test reports that involve alternate models or layups.
- Disguising an armor’s true strength by omitting crown shots.
- Publishing armor weights and sizes with wide tolerances.
- Establishing affiliate links with social media outlets that claim to be objective.
- Pushing spam through online discussion boards.
- Lack of transparency in armor design, planning, purpose and customer education.
Just because a company has an NIJ certified plate or two doesn’t restrict them from engaging in suspect behaviors. Either buy the NIJ certified models OR establish a relationship with your manufacturer so you are confident in the product. See if they will send you pictures of your armor being made, answer technical questions, or take a phone call. These are positive signs.
One of the absolute worst things a manufacturer can do is publish wide size and weight variances. When manufacturing the same plate to a repeatable standard, there is no massive variance like .2 pounds or 5%. The plate design and production methods produce very close weights every time.
Manufacturing techniques and components
From a consumer’s perspective, it is important to have some technical knowledge about manufacturing techniques. The following are just my opinions and I pass them along for consideration or rejection.
Ceramic
Very few armor manufacturers produce their own ceramic. There are various sources throughout the world through which quality ballistic ceramic can be obtained, many offering the ability to open molds. Manufacturers will advertise that their ceramic is a custom blend or assign some special name to it. In reality, RF3 alumina is most often 7.5mm, 9mm or 10mm and comes in either 98% or 99.7% purity. There is not much “customization” available, and most of the time that is just marketing.
Polyethylene (PE)
Most modern ceramic armor is comprised of a ceramic strike face and a UHMWPE (PE) backing material. Unlike the ceramic, PE must be processed for use. PE arrives on rolls as a finished material, generally about 64” wide, and is often unidirectional (UD). Since “off the roll” PE cannot be adhered directly to ceramic effectively, it must be consolidated — processed from its sheet-like form to a hard backing material through heat and pressure.
Image 11: Pre-processed roll of UHMWPE backing material.
Video 4: PE after consolidation.
There are two main ways to consolidate PE:
1. Via high tonnage press. Most PE is consolidated by about 1000-ton machines that press between 3500-5000 psi while heating to approximately 266°F. High force generally results in more comprehensive consolidation that holds up well under ballistic stresses. The main disadvantage is that once consolidated, additional processing is required to bond the ceramic — typically reheating under vacuum to activate an adhesive sheet. PE is very sensitive to heat; an improperly calibrated oven or long dwell near the melt range can degrade it. A select few builders use proprietary adhesive blends that mitigate the heat threat with extended dwell times at lower temperatures.
2. Autoclaving. This method bonds the ceramic strike face while PE consolidation occurs — one-step processing that saves time and provides flexibility to shift between ceramic shapes. The real difficulty is PE delamination possible during ballistic impacts, since some autoclaves operate well below the pressure of a high tonnage press. I would recommend autoclave pressure capability of at least 300 PSI.
Manufacturers may operate their own presses or autoclaves or spec the consolidation out to an expert third party. In my experience with reputable partners, there is no discernible difference in resultant hard PE shapes. Remember that the proof is in the manufacturer’s performance as indicated in proper ballistics testing and transparency.
There are many types of PE. Some are “harder” and show less BFD; others are softer and have more BFD but accommodate the stretching required of multi-hits. My favorite PE has a water-based polyurethane resin and performs well in multiple strike scenarios.
Adhesives
Adhesives are one of the most important elements of a ceramic armor plate. For an armor plate to work properly and safely, the materials must be kept in close proximity; any separation results in decreased performance. If you separated the ceramic strike face and the PE backer by 1”-2”, you would see markedly reduced effectiveness and possibly a complete penetration of both materials.
The types of adhesives used worldwide are tied to geography. Armor built in China normally incorporates cyanoacrylate, chloroprene rubber or neoprene liquid type adhesives, manually applied via squeegee, with the ceramic applied and allowed to cure. This accounts for the vast majority of low-priced armor imported into the USA and can suffer from inconsistent layer thickness and weak bonds with low-energy PE.
Video 5: General methodology for assembling retracted strike face armor.
For maximum strength, a thermally-activated adhesive sheet may be used. This produces consistency in the adhesive layer — more uniform in thickness and relatively free of air bubbles under pressure. The image below shows an adhesive sheet (pre-processing state) resting between the ceramic and the PE layer.
Image 12: A uniform adhesive sheet resting between ceramic tile and the PE backing material.
Most adhesives emit volatile organic compounds (VOCs) until fully cured. You can locate manufacturers that use proprietary low VOC, RoHS and/or CA Prop 65 compliant materials. These are safer to use and will not have offensive odors when delivered to consumers.
Fiberglass backing plates
Some manufacturers still produce ceramic armor plates with fiberglass (E-glass or S-glass) backing materials. These are heavy and do not resist steel penetrators as well as PE backers. I would suggest sticking with PE backing materials.
An example armor plate comparison
A consumer wants to purchase an RF3 (Level IV) multi-curve armor plate. He narrows the search to the following two products and selects Model A because there is an NIJ-accredited lab report for a crown shot, he likes the higher purity tile, and there is transparency regarding total weight.
| Model A | Model B |
| RF3 | RF3 |
| Full 10” x 12” size | 9.75” x 11.75” |
| 7.1 pounds | 6.8 pounds with a “.2 pd” or “5%” weight variance |
| multi-curve | multi-curve |
| 99.7% pure ceramic | 90% pure ceramic |
| NIJ lab crown shot | Two shots in corners - no crown shot |
Statement about foreign armor
I have tested hundreds of armor plates from around the world built by third parties. The vast majority of armor sold within the United States is made in China. Is Chinese armor effective? The answer is simple: performance tells the truth. Many readers will end up purchasing Chinese armor, so I want to provide some general advice. Chinese-built armor has some shared characteristics:
- often built from mosaic style tile arrays (50mm pieces)
- incorporates a 1” foam ring (retracted strike face)
- resellers do not disclose the retracted strike face
- weighs around 5 pounds for Level 3+ (RF2) or 6.2 pounds (RF3)
- uses liquid adhesives (no pressure or heat in build formula)
- performs on par with most US domestic brands if built by reputable companies
- some say “Made in USA” but are Chinese brands
Most consumers making armor purchasing decisions are extremely price sensitive and opt for a tested, less expensive Chinese brand. Trying to compete is difficult due to low costs, but also because consumers really don’t take the time to educate themselves on armor specifics.
The below ceramic armor plate was made in China. The cover was removed and a photo taken of the strike face.
Image 13: Showing a poorly fitted ceramic mosaic tile array armor plate.
As imported armor arrives, the covers obscure the tile pattern fit, and it is problematic to remove the covers without damaging the plate. As a result, the armor is never disassembled for inspection. This lack of transparency is an unmitigated risk. Importantly, poor tile fit is not because it is from China — it is the result of bad workmanship, and it happens in the US also. There are plenty of examples of excellent performance on NIJ certified lab tests for Chinese armor — some outperform the most well known domestic brands. There are also examples of bad performance.
Another thing to watch out for is an importer that rebrands armor and claims it is “Made in USA.” Check their website and social media. Do they offer to send you photos of your armor being built? Can they prove it is Made in the USA? Manufacturers should earn your trust with transparency. If they cannot or will not, then move on.
Appendix A - Terminology
The following terms are drawn from the NIJ 0101.07 Standard, Section 3, and ASTM E3005, paraphrased for brevity.
backface deformation (BFD) — The indentation in the backing material caused by a projectile impact during testing.
ballistic limit — A measure of an item’s ballistic resistance to complete penetration, expressed as a velocity associated with some probability of perforation.
complete penetration (CP) — A failure in which any portion or fragment of the test threat passes through the wear face or into the backing directly behind the item.
crown — Location of the highest point of a plate, at the intersection of multiple different curvatures.
hard armor — An item of personal protective equipment constructed of rigid materials; synonymous with hard armor plate and plate.
in conjunction with armor — Soft or hard armor designed to provide a specific level of ballistic protection only when layered with a specified model of body armor.
monolithic — A single-piece ceramic strike face.
mosaic (tile array) — A strike face built from multiple individual ceramic tiles.
obliquity — The angle between the test threat line of aim and the line normal to a reference plane based on features of the test item at the point of aim.
partial penetration (PP) — Any result of a test threat impact that is not a complete penetration; synonymous with stop.
strike face — The surface of an armor panel or plate intended to face the incoming threat.
wear face — The surface of an armor panel or plate intended to be placed against or proximal to the wearer’s body.
For technical questions or to discuss which configuration fits your needs, contact Gilliam Arms at info@gilliamarms.com.
