Level 3A vs 3 vs 4 Body Armor | Guide to Body Armor Levels

Level 3A vs 3 vs 4 Body Armor | Guide to Body Armor Levels


If you want to stop standard handgun bullets: Level 3A body armor

If you want to stop assault rifle bullets: Level 3 body armor

If you want to stop high caliber armor penetrating bullets: Level 4 body armor

Note: Atomic Defense Level 3A body armor also stops 12 gauge slugs and buckshot

Body armor has always been one of the most important things in combat environments, from ancient warriors wearing hardened hide, to knights in shining armor, to modern day marines in ballistic vests. Nowadays people will laugh at you if you show up in a full suit of plate mail to a fight against assailants armed with AK-47’s. Those sheets of metal may be able to stop a sword, but they’re not stopping a bullet. 

This is why you want more modern armor, which comes in several NIJ classifications. (more on NIJ later) The classifications are 1, 2A, 2, 3A, 3, and 4 body armor, each protects against progressively higher calibers. We’ll be focusing on 3A through 4, the three stronger classes of body armor. We don’t recommend you even looking into anything below level 3A.  It won’t stop some very common calibers that you’ll run into.

Deciding what level of body armor you want can be a decision that saves your life, and requires a lot of thought and research. Your decision of what kind of armor you’ll be rockin’ into a high combat zone or for home defense could be the difference between life and death, or anything else.

 Some things to keep in mind are that different NIJ standard levels of body armor are intended for varying degrees of threat in combat, some are flexible and some are rigid, some are light and some are very heavy, some can withstand multiple shots in a small area whereas some can only block multiple shots in a larger area. 

I know, I know, lots of info that requires lots of research, luckily enough, we’ve compiled a quick and easy breakdown of the three highest levels of body armor. 

First, what the heck is NIJ!? NIJ, or National Institute of Justice, is the research, development and evaluation agency of the U.S. Department of Justice. NIJ is the team that determined the standard levels of body armor. They did thorough research and testing on different types of body armor to develop this standard, and it’s the body armor standard used in the body armor industry when creating or improving modern body armor. The NIJ uses Roman Numerals for their levels, which can be translated as such:


3 = III

4 = IV

Let’s start with the lowest level of the three: 3A.

This armor is the best if all you’re going up against are handguns and in the case of Atomic Defense’s 3A body armor 12 gauge shotgun slugs and buckshot (this is a step up from what other sellers offer), it’ll hurt a helluva lot to take a slug to the chest from a shotgun, but you’ll be alive, what more could you ask for? Am I right? Moving along…

 3A level body armor is the weakest of the three in this list, but it’s also the lightest of the three, so jogging down the block won’t feel like running a marathon. It’s not rigid, meaning, it can be folded around the body. This body armor is intended to protect against everything levels 1-2 protect against (which includes smaller caliber firearms), all the way up to .44 Magnum and 9mm FMJ (full metal jacket) firearms. Also, due to its versatility, 3A is the level of body armor that the police almost always use now. 

So as a recap, level 3A body armor:

  • Is weaker than 3, but stronger than 1, 2A, and 2
  • Isn’t rigid (it’s made of a flexible material and can be folded around the body
  • Is lighter than 3 and 4
  • Provides protection up to .22, .25 ACP, 40, 45, 38 spc, .380, .44 Magnum and 9mm (Atomic Defense’s level 3A body armor also protects against 12 gauge shotgun slugs and buckshot)

Next level in the list: 3.

This is the second strongest of the NIJ levels of body armor, and is the first level that protects against assault rifle rounds. This body armor is suggested if there’s the chance someone will be coming at you with an assault rifle. If you’re in this situation and you don’t want your chest to look like grandma’s old pincushion that hasn’t been replaced since 1963, you’re going to want some level 3 body armor. 

Level 3 body armor protects against all calibers lower levels of body armor protect against, but it also protects against: multiple shots from 7.62 FMJ, 5.56 FMJ, 30 carbine FMJ, and 12 gauge rifled slugs. This level of body armor is heavier than 3A, but lighter than 4. This armor type is also rigid, meaning it is not flexible, and must come pre-folded.

This is arguably the best all around body armor level, simply because it can protect against multiple shots. Once again, this is another one where Atomic Defense takes it to the next level.  Atomic Defense level 3 body armor can stop soft soft-steel and lead rounds.  Well before some competition. 

To recap, level 3 body armor:

  • Is weaker than 4, but stronger than 1, 2A, 2, and 3A
  • Is rigid (it’s made of a hard material and must come pre-folded)
  • Is lighter than 4, but heavier than 3A
  • Provides protection from multiple shots from 7.62 FMJ, 5.56 FMJ, 30 carbine FMJ, and 12 gauge rifled slugs
  • Comes as an insert for a vest

Last but certainly not least: level 4. 

This is the highest level of body armor and protects against the highest caliber rounds of all the body armor levels. This is the armor that Rambo would’ve worn if he didn’t have indestructible plot armor.

Anyways… This armor provides the most protection of all NIJ levels of body armor. This high performance level of protection does have a few drawbacks though. It is rigid, meaning it can’t be folded to the body. It’s usually heavy, so don’t skip leg day if you’re going to be running in this thing. However, you can skip leg day with Atomic Defense level 4 armor plates.  They are between 5 and 7 pounds, depending on the size of plate.

All reasonably thin level 4 armor is going to be ceramic, otherwise it will be extremely heavy and very bulky. In addition to protecting against the same caliber bullets as all other levels of armor, it also protects against .30-06, .308, 30-30, and countless other armor piercing bullets. You know what time it is, recap time. 

Level 4 body armor: 

  • Is the strongest available NIJ level of body armor
  • Is rigid (made of hard material, typically ceramic)
  • Is heavier than all other levels of armor
  • Provides protection against all calibers of previous levels of armor, but also includes protection from 5.56 AP/API, 7.62x39 AP/API, 7.62x51 AP/API, 7.62x54 AP/API, .30-06 AP/API, .308 AP/API, 30-30 AP/API

So, which one is best? That depends entirely on what kind of world you'll be living in. Will you be in the middle of a possible gunfight, with AK-47’s and M4’s firing everywhere, or do you just want to always be prepared in case something happens.

Take a close look at all the information provided here and make your best educated decision. There’s a lot to keep in mind here, hopefully this has helped you find out what NIJ level of body armor is best for you.

Oh, and don’t forget to use discount code: SJ78 for 5% off at checkout! If you still need help with choosing one, just let us know.  We can show you the option that is perfect for you. You can contact me using this email: stephen@atomicdefense.com Thanks for reading and take care! 


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