Level III vs Level IIIA Body Armor | What's The Difference?

Level III vs Level IIIA Body Armor | What's The Difference?

The National Institute of Justice (NIJ) is the governing body for ballistic protection in the United States. There are 5 distinct standards that are classified based on the caliber of bullet it's able to protect against. In this blog, you'll find everything you need to understand Level III and Level IIIA body armor.

Level/Type IIIA Body Armor

According to the NIJ, Level/Type IIIA body armor defeats a .357 Sig FMJ Flat Nose (FN) weighing less than 8.1 grams or 125 grain.

The muzzle velocity must be under 1,470 ft/per second at this weight for a Level IIIA to stop the bullet.

Level IIIA will also defeat a .44 Magnum Semi Jacketed Hollow Point (SJHP) if it weighs less than 15.6 grams (240 gr) and a muzzle velocity of slower than 1,430 ft/s.

Level/Type IIIA armor that has been conditioned can defeat a .357 Sig FMJ FN weighing 125 grain, but with a reduced velocity of 1,410 ft/s.

A .44 Magnum SJHP weighing 240 grain and a muzzle velocity of 1,340 ft/s will NOT penetrate a conditioned Level IIIA armor system. 

What is Conditioned Body Armor?

Conditioned armor emulates the environmental conditions that the wearer of the armor will be exposed to in the field. For example, if you’re wearing Level IIIA armor in the south, temperatures can reach well above 120℉.

In places, such as Florida, Georgia, Mississippi, and Alabama, the humidity in the summer averages 80%. These extreme temperature conditions can have a negative impact on the practicality of the armor.

ShotStop Level III body armor

The NIJ exposes every armor they test to these conditions to ensure they can hold up in extreme environments. 

Once you put the armor through the temperature and humidity conditioning tests, it’s put through a mechanical damage test.

This test is called the tumbler test, which comprises the armor being placed in a drum machine and tumbled around inside like a clothes dryer.

The point of this test is to emulate the wear and tear of the armor by throwing it around in a controlled environment. They test all Armor before conditioning and after conditioning to get a complete analysis of the armor’s capabilities. 

Level/Type III Body Armor 

Level III body armor is stronger than Level IIIA because it defeats rifle caliber rounds. Level III will always have a hard plate insert that must be tested in a conditioned state.

The NIJ tests Level III conditioned armor against a 7.62mm FMJ (M80 military) weighing 147 grain and a muzzle velocity of 2,780 ft/s. A 7.62x39mm FMJ is normally fired from an AK-47 style rifle.

ShotStop Level III Body Armor

This ensures Level III armor will stop a 5.56mm FMJ bullet fired from the most common AR-15 models. 

Level III flexible armor is required to be tested in both new and conditioned state to get a complete understanding of its capabilities.

They test flexible armor with the same specs (147 grain, 2,780 ft/s, and 7.62mm) as the hard plate.

The biggest difference is the flexible armor must be tested with the hard armor.

Make sure you understand that flexible armor rated at a Level III will not stop a 7.62mm (.308) bullet without the hard armor insert.

The NIJ will not approve of any flexible armor replacing a hard plate unless there are at least 2 flexible plates with each other. 

What is In-Conjunction With Armor (ICW)?

According to the National Institute of Justice (NIJ), ICW armor is the combination of 2 separate flexible armor plates or a flexible plate with an armor insert.

ICW armor offers protection against higher caliber bullets or added stab-resistant capabilities.

For an ICW armor system to pass the strict NIJ standards for Level III, they must be tested together.

If the flexible armor is stab-resistant, the label must specify which level of stab-resistance (level 1,2,3) it’s approved for. The NIJ standards for stab-resistant armor can be found here. 


What is The Difference between Level IIIA and Level III Body Armor?

Level 3A armor is always going to be a flexible armor that's intended to stop handgun caliber bullets, up to a .44 Mag.

NIJ Level IIIA Body Armor NIJ Level III Body Armor
Caliber's Tested
  • .357 SIG
  • .44 Magnum)
  • 7.62 x 51mm FMJ (M80)
Bullet Weight
  • 125 gr (.357 Sig)
  • 240 gr (.44 Mag)
  • 147 gr
Bullet Velocity 1,470 FT/Sec 2,780 FT/Sec
Armor Type Soft Armor Insert Hard Armor Insert
Threat-Level Protection
  • 9mm
  • .38 Special
  • .40 S&W
  • .45 ACP
  • .357 Sig
  • .357 Mag
  • .44 Mag
  • 9mm
  • .38 Special
  • .40 S&W
  • .45 ACP
  • .357 Sig
  • .357 Mag
  • .44 Mag
  • 5.56 x 45mm NATO (M193)
  • 7.62 x 51mm (M80)
  • 7.62 x 39mm


What is the FBI’s Law Enforcement Officers Killed and Assaulted (LEOKA) Program?

The LEOKA program is a database that monitors officer interactions with the public. It actively monitors how officers are injured, killed, what weapons were used, and where the incident happens.

When deciding which body armor you want/need, it’s important to look at the statistics of police who are killed on duty.

As grim as this is to research and discuss, knowing how officers are dying in the streets will help you make better decisions. 

LEOKA weapon distribution

According to the FBI, the most dangerous places for law enforcement officers are the southern and western regions of the United States. 

How Many Lives Have Been Saved By Body Armor?

With dozens of LEOs killed every year from guns, we sometimes forget body armor has saved how many more. According to the FBI, from 2002-2011, 498 police officers were killed by firearms.

In that same time period, over 2,000 police officers have been saved by wearing body armor.

According to the International Association of Chiefs of Police (IACP) /Dupont Kevlar Survivors Club, over 3,100 LEOs have been saved up to the year 2018.

With thousands of lives saved up to this point, there is no excuse to not wear body armor while on duty. 

ShotStop body armor

Why Do I Need To Know The FBI Stats?

Knowing how criminals are fighting against law enforcement will help you make the best decision on what level of protection you need.

With most officers being killed by gunshots to the neck or head, why does body armor matter?

The short answer is by wearing armor, you reduce the size of the target. This makes the shooter aim for a smaller target, rather than shooting at your chest or back. This will increase your chances of survival in a shooting while on duty. 

Who Should Wear Level IIIA Body Armor?

Level IIIA body armor defeats all handgun bullets (up to .44 Mag). Level IIIA is what I would wear if I were a patrolman that spends most time in a police car.

However, the NIJ conditioning tests reveal degraded resistance from Magnum caliber bullets in humid environments.

For example, if you’re a police officer in the south or western region of the U.S., be safe and go with a Level III. 


Who Should Wear Level III Body Armor?

Level III body armor can defeat rifle caliber bullets, such as 7.62mm and non-military grade 5.56mm bullets.

Level III armor is what I recommend for daily use for police officers, security guards, and federal law enforcement agents (F.B.I., A.T.F., and N.S.A.). The ability to defeat all handguns and most rifles will ensure your safety in most cases.

Level III armor is harder to conceal underneath your clothing, but will offer better protection than the IIIA. 

bald sheriff w:armor.jpg


LEOs wear level/Type IIIA and Level III in both civilian and federal government forces. Level IIIA armor is going to stop every handgun caliber round up to a .44 Magnum.

Since most LEOs killed and wounded are by small arms, such as handguns, Level IIIA is sufficient for normal police use. Level III armor withstands the shot from an AR-15 and other sporting rifles.

Regardless of which armor you choose, think about the perceived threat you’re going to face in your day. This will help guide you in your decision to use either Level IIIA or Level III armor. 

Older Post Newer Post


  • AJ, of course a level 3a is better than nothing! That’s a stupid question as it’s always going to be better than nothing. School shooters often have handguns too so get the 3a and have them use that until they can carry the 3! It’s probably only a matter of time before Biden bans body armor. Instead of Biden hiring 87,000 IRS agents it sure would’ve been better to hire that many school officers or maybe half to the schools and half to the border! Vote red…common sense over nonsense!

    Joe P on

  • Very confusingly worded in some areas like the mention of level III that is tested to stop M80, which is 7.62×51mm NATO and then bringing up Soviet 7.62×39mm and going on to say it will stop 5.56.
    UHMWPE plates can be level III and stop M80 lead ball but M855 (no longer used by the military and has long been sold to civilians anyway) will zip right through it.
    There is also level III and IV flexible armor like Dragonskin.

    JimP on

  • Hi! I came across this blog because I am looking for bulletproof backpack inserts for my kids. It seems like I would need a level III to protect against what is commonly used in school shootings, but that is going to be way too heavy for my kindergartner. Is a level IIIA better than nothing, or would it be useless in that scenario?

    AJ on

  • Thank you very informative.

    paul on

  • Hi Dan Thanking for sharing. It’s very useful and help me for working body armor project in my country.

    May I ask you why?
    NIJ L.3 not recognize 5.56mm?

    Thank you

    Tanakorn on

Leave a comment

Please note, comments must be approved before they are published