The AR-15 is one of the most popular rifles and comes in a variety of different calibers. For this question though, I’ll use the most common .223/5.56mm caliber.
Yes, an AR-15 can penetrate lower level rated bulletproof vests such as levels 2A, 2, and 3A. However, bulletproof vests rated levels 3 and 4 will be able to stop the most common AR-15 cartridge, the .223/5.56mm rounds.
Different levels of body armor will be able to stop different rounds with lower levels mainly used to protect against handgun ammunition and the higher levels better against rifle rounds.
Will a 5.56 Penetrate a Vest or Body Armor?
Yes, an 5.56 can penetrate lower level rated bulletproof vests such as levels 2A, 2, and 3A. However, bulletproof vests rated levels 3 and 4 will need an armor piercing 5.56 round like a steel or tungsten carbide core to be able to penetrate.
It depends which type of vest you’re shooting at but even modern body armor can be penetrated by the right 5.56 ammunition. The most popular and easy to wear body armor is really only rated for handgun rounds.
If you want to stop a rifle cartridge, you’ll want the more advanced plated armor. But even then, armor piercing ammunition can still make it’s way through heavy plates and advanced armor.
Body Armor Levels of Protection
There are five levels of body armor as defined by the National Institute of Justice (NIJ) taking into account which calibers a body armor can stop and the ability to resist bullet penetration.
The weight of the bullet, velocity, and distance all play a part in a body armors effectiveness. Other factors to consider that don’t relate to its bullet stopping ability are mobility, cost, and how easy the armor is to conceal.
Level IIA
Level IIA body armor is lowest level body armor on the market. It’s mostly used to stop smaller, slower, handgun caliber rounds. Usually constructed using a woven fiber approach, this body armor is usually very lightweight and easy to wear.
This is the type of body armor you wear that you want to easily conceal, don’t want to feel constricted. This is also one of the most affordable options.
Keep in mind, although it will stop some 9mm rounds, it won’t stop all of them. Also, this armor isn’t known as being able to stop trauma from the round very efficiently.
Capable of stopping:
- 9mm at 1150 fps
- 40 S&W FMJ at 1050 fps
- .45 ACP FMJ at 900 fps
Level II
This type of body armor is by far the most popular body armor for stopping handgun rounds and preventing trauma from those rounds while also remaining concealable and affordable.
Capable of stopping:
- 9mm 124gr at 1300 fps
- .357 Magnum at 1425 fps
- 45 ACP
- 40 S&W
- .380 auto
Level IIIA
This armor is usually still considered soft body armor, similar to the level II and level IIA, it is made of woven fibers that are meant to stop a bullet. Of course this level IIIA body armor will be thicker, and some versions do come in hard type body armor.
In order for body armor to be considered level IIIA it needs to be able to stop a .240gr 44 Magnum travelling at 1340 fps.
Capable of stopping:
- Everything level II and IIA stop
- 9mm
- .357 Sig
- 12 gauge shell
Level III
This is the first in our list rated to stop rifle rounds. Many rifle rounds aren’t necessarily heavier than handgun rounds, but they are travelling much faster.
That’s why this armor is referred to as hard armor. It’s very thick and usually accompanied by hard metal rifle plates of some kind.
Capable of stopping:
- 7.62x51mm 147gr at 2775 fps (.308)
- 7.62×39 (AK-47)
- 5.56mm/.223 (AR-15)
Level IV
This is the highest level of body armor according to the NIJ classification and is made to stop at least one armor piercing round. Keep in mind, it isn’t required too and may not be able to stop multiple armor piercing rounds.
Capable of stopping:
- Everything in the lower levels
- One armor piercing rifle round
- 30-06 166gr at 2860 fps
Can an AR-15 Shoot Through A Door
Yes, an AR-15 can shoot through a door. Most calibers shot through the AR platform will be able to penetrate a standard house interior or exterior door. A steel door will be able to stop smaller, slower moving, AR-15 calibers.
Most interior doors are hollow, and even the solid ones aren’t made of anything that will stop a bullet. Almost every caliber will penetrate an interior door.
Even most exterior doors now a days are plastic and will be easily penetrated by an AR-15. The exception being thick steel security doors.
They do sell steel doors at a decent price so many people buy the steel exterior doors. But those steel doors are thin sheets of metal. You would need thick steel security doors to stop a bullet. Even then, some armor piercing ammunition may still penetrate the door.
What Can Stop a 5.56 Round?
Level III and level IV body armor are able to stop a 5.56mm round. AR500 steel plates 3/8″ thick are used as shooting targets for 5.56mm used at 100 yards and are made to deflect and stop the round as well. However, multiple armor piercing 5.56mm rounds can penetrate body armor.
There’s a lot of things that can stop a 5.56mm round, like a tree for example. The important thing to remember is that distance from target, velocity, and how many rounds are fired all affect what type of body armor or targets the 5.56mm will penetrate.
