At Garrett, we have spent decades building weapon detection technology, and we hear the same question from security teams again and again: what exactly can these systems detect, and what might they miss? It’s a fair question, and one every security professional deserves a clear answer to before they rely on this equipment to protect people.
One of the biggest gaps we see across the industry is that metal detectors from certain manufacturers are only built to detect ferrous items, meaning iron and steel based metals like those found in most traditional firearms and knives. Garrett security detectors are engineered differently, designed to detect both ferrous and non-ferrous metals, which helps close a coverage gap that many other systems simply were not built to address.
Our team at Garrett will break down exactly what weapon detectors and metal detectors detect, why detection capability differs from one device to the next, and what to look for when choosing the right system for your facility.
Key Takeaways
- Weapon detectors work by generating a magnetic field and sensing disruptions caused by conductive metal, not by recognizing weapon shapes.
- Detectors generally target three threat categories: firearms, bladed weapons, and the metal components of explosive devices.
- Ferrous-only detectors can miss non-ferrous weapon components, leaving a real coverage gap that facilities should be aware of.
- Secondary screening methods, like hand-wanding, remain essential even with advanced detection technology.
- Choosing the right system means matching detection sensitivity, false alarm rates, and throughput needs to a facility’s specific threat profile.
- Garrett designs its detectors to catch both ferrous and non-ferrous metals, aiming to close the gap left by many ferrous-only systems.
How Weapon Detection Technology Works
Most weapon detectors work by generating a magnetic field and measuring how that field reacts when a metallic object passes through it. Metal disrupts the field in a measurable way, and the metal detector’s sensors pick up on that disruption to trigger an alert. This is the same basic principle behind both walk-through units and handheld wands, though the strength and shape of the field can differ quite a bit depending on the design.
Because this technology depends on detecting conductive mass, not on recognizing the shape of a weapon, detection capability depends heavily on the type of metal involved and how the device is calibrated.
This is exactly why we engineer our weapons and metal detectors at Garrett with careful attention to sensitivity and metal type, since two detectors marketed for the same purpose can perform very differently in the field. Understanding this principle helps explain threat categories and metal type differences.
The Three Main Threat Categories Weapon Detectors Identify
Weapon detectors are generally built to flag three broad categories of threats. These categories cover the vast majority of items security teams are trained to look for at checkpoints, whether at a school, stadium, courthouse, or airport, and they shape how we design our own detection systems. The table below summarizes the main categories and common examples within each one.
| Threat Category | Common Examples |
| Firearms | Handguns, rifles, assault weapons |
| Bladed Weapons | Metallic knives, swords, box cutters |
| Explosive Device Components | Detonators, battery packs, metallic IED casings |
Firearms
Firearms are the most well known target of weapon detection systems and metal detectors, and for good reason. Handguns, rifles, and assault weapons all contain enough ferrous metal in their frames, barrels, and mechanisms to reliably trigger a properly calibrated detector.
That said, detection strength can vary depending on the firearm’s size and metal composition. Smaller handguns with more plastic or polymer components may produce a weaker signal than a full metal rifle, which is one reason we build adjustable sensitivity settings into our equipment so security teams can fine tune performance in the field.
Bladed Weapons
Metallic knives, swords, and box cutters fall into this category, and they are generally detectable as long as they contain enough metal mass. A large kitchen knife or a sword will almost always trigger an alert because of its size and metal content.
Smaller bladed items, like a thin box cutter blade or a small folding knife, can be harder to catch for less advanced weapons detection systems. These items have less metal mass, which means they produce a weaker magnetic disruption and often require the kind of refined sensitivity we build into our metal detectors to catch reliably.
Explosive Device Components
Weapon detectors do not detect explosive material itself, since most explosive compounds are not metallic. Instead, they detect the metal components often used to build explosive devices, including detonators, battery packs, and metallic IED casings.
This distinction matters a lot for training purposes. Security staff need to understand that a detector alert tied to explosive components is really an alert on metal parts, not a direct detection of the explosive substance, which is why layered screening procedures remain important at high-risk facilities.
Not All Metal Detectors Detect the Same Metals
One of the biggest misunderstandings in security screening is assuming all metal detectors catch all types of metal equally well. In reality, the type of metal involved plays a huge role in whether a detector will pick it up at all, and closing this gap has been a major focus of our work at Garrett. Understanding the difference between ferrous and non-ferrous metals is essential for any team evaluating or operating a weapons detection system.
Ferrous vs. Non-Ferrous Metal Detection
Ferrous metals are iron based, and they include materials like steel, which is the primary component in most firearms and knives. Non-ferrous metals, on the other hand, include materials like aluminum, copper, and certain alloys that do not contain iron.
Most standard walk-through and handheld metal detectors are optimized primarily for ferrous metal detection, since that covers the majority of traditional weapons. At Garrett, we go further, engineering all of our detectors to pick up both ferrous and non-ferrous metals, which helps close a detection gap that other equipment often misses entirely.
Why This Gap Matters for Threat Screening
If a facility only uses ferrous-focused equipment, certain non-ferrous weapon components can slip through undetected. This includes items such as:
- Non-ferrous alloy blades
- Certain firearm parts made with lighter metals
- Other non-ferrous hardware that could be part of a weapon or device
The real-world implication is serious. A person carrying a weapon component made primarily of non-ferrous metal could walk through a ferrous-only detector without triggering an alarm at all, giving security staff a false sense that the area is clear when it is not. This is precisely the kind of gap we built our detection technology to address.
Why Traditional Metal Detectors Aren’t Weapon-Specific
Metal detection technology has come a long way, but at its core, a traditional metal detector simply detects conductive metal mass – it can’t tell a weapon from an everyday object. That means harmless items trigger the same alert as real threats, slowing lines and frustrating security staff.
The Garrett Paragon solves this. It’s the first product to run software built on Clarity™, Garrett’s new AI-enhanced development platform – a proprietary deep learning system designed to push detection performance beyond what’s traditionally been possible. The Paragon uses this advanced technology to help security teams separate everyday items from genuine threats, including:
- Detection zones: 66 distinct zones, with left, center, and right identification across 22 horizontal bands
- Sensitivity levels: 200 adjustable levels for precise, high-threat target discrimination
- Integrated programs: 23 or more security programs built to detect weapons while filtering out everyday items
With Clarity now powering ongoing improvements to detection and indication, Paragon units benefit from these deep learning-driven enhancements – and 2026 is expected to bring further gains across both new and existing Garrett security products.
This level of precision is how we help security teams cut down on false alarms without sacrificing detection performance, keeping checkpoints moving while still catching what actually matters.
The Role of Secondary Screening
Even with advanced weapons detection systems like the Paragon, secondary screening steps like hand-wanding remain an essential part of the process, especially in high-security environments like airports or government facilities.
Skipping secondary screening with a handheld detector or rushing through it undermines the entire purpose of having a detection system in place. This is why we built the Garrett Guide, a handheld metal detector designed to help security teams quickly conduct thorough and consistent secondary screening.
Choosing a Weapon Detection System Based on Detection Needs
Selecting the right weapon detection system starts with understanding the specific threats a facility is most likely to face. A courthouse, a school, and a concert venue all have different risk profiles, and we work with each customer to make sure the technology matches that reality.
Before making a purchase, security teams and procurement decision-makers should ask a few key questions to make sure the system fits their actual needs.
Questions Security Teams Should Ask Before Purchasing
Buyers should first ask what metal types the system detects, since ferrous-only equipment leaves a real gap when it comes to non-ferrous weapon components. It also helps to ask about the system’s false alarm rate, since a device with a high false alarm rate can slow down checkpoints and frustrate both staff and visitors.
Two more questions matter just as much. Buyers should ask whether the system requires secondary screening as a standard part of its workflow, and whether the device is suited for high-traffic environments like schools, stadiums, or office buildings, since throughput speed and sensitivity needs differ a lot between these settings. Our team is always available to walk customers through these questions before they buy. You can easily contact us for more information.
Matching Technology to Threat Environment
High-risk facilities generally need more sensitive detection and stricter secondary screening protocols than general public venues like retail stores or office lobbies. The threat level of the environment should directly shape how a system is calibrated and staffed.
The right detector for your environment comes down to knowing your test targets. Can it reliably detect your smallest threat item, even if it’s nonferrous? And can it do that while still meeting your throughput requirements?
A system that catches everything but slows checkpoints to a crawl isn’t a workable solution – and neither is one that moves fast but misses the targets that matter most. The goal is finding the balance point where detection accuracy and flow both hold up under real-world conditions and that’s where the Garret Paragon shines.
How Garrett Uses AI to Enhance Development Of Our Weapons Detection Systems
At Garrett, we continue to invest in the technology behind our detectors through Clarity, our proprietary deep learning based development platform. Clarity has already been used to improve detection and indication for the Paragon walk-through metal detector, and in 2026, it is expected to enhance both new and existing Garrett products.
- Clarity is a proprietary, deep learning based platform built to improve detection accuracy
- It has already been used to enhance detection and indication on the Paragon
- Future updates will extend these improvements to both new and existing Garrett products
- Clarity was developed at Garrett’s Garland, Texas facility with patent and trademark protections in place
All Paragon units running software version 2.00.1 or later come equipped with these Clarity developed improvements, giving customers better detection without new hardware. This is exactly why we encourage potential security customers to invest in Garrett security products, ensuring their facility gets the most advanced screening available in the market today.
Understanding What Weapons Detectors Can Detect
Weapon detectors are built to catch three main categories of threats: firearms, bladed weapons, and the metal components used in explosive devices. Understanding this scope helps security teams set realistic expectations for what their equipment can and cannot do.
The biggest factor in overall detection performance often comes down to ferrous versus non-ferrous capability, since equipment that only catches ferrous metals can leave real gaps in coverage. At Garrett, our detectors are built to cover both, and we encourage every security team to evaluate their current equipment against their facility’s specific threat profile to see whether it truly matches the risks they are responsible for screening against.
Not sure whether your current detection system covers everything it should? Our team at Garrett is here to help you find the right fit for your facility, whether you have a quick question or need a full walkthrough of your options. Contact us today to learn more.