Does M855 Penetrate Body Armor?

NSSF has learned from Winchester Ammunition that they were being told that M855/SS109 ammunition sales to civilians from the Lake City, Mo., facility are on the chopping block.

That would potentially choke off over 30 percent of the ammunition used on AR-15 rifles by law-abiding citizens.

It would also risk the jobs of up to 500 employees and the Defense Department’s ability to surge ammunition production during increased operational tempo periods. One of the most common questions that get asked about M855 is can it penetrate body armor?

Does M855 Penetrate Body Armor?

How Is Armor Piercing Ammunition Defined?

AP (Armor-Piercing) ammunition is designed to defeat ballistic armor intended to defeat conventional bullets. The GCA (Gun Control Act)  defines "armor piercing ammunition" as:

  1. A projectile or projectile core that may be used in a handgun and which is constructed entirely (excluding the presence of traces of other substances) from one or a combination of tungsten alloys, steel, iron, brass, bronze, beryllium copper, or depleted uranium; or
  2. A full jacketed projectile larger than .22 caliber designed and intended for use in a handgun and whose jacket has a weight of more than 25 percent of the total weight of the projectile.

Both parts of the above definition apply specifically to bullet construction and to their use in handguns. This goes back to the Law Enforcement Officer’s Safety Act which was intended to regulate "cop-killer" bullets from use in concealable handguns. M855 does not fall into the category or definition of armor-piercing ammunition.

Will M855 Defeat Body Armor

The short answer is no. M855 is not classified as an Armor Piercing round, neither literally nor by the BATFEs description of what an AP round is. It’s rated for use against light personnel and thin-skinned vehicles for military and law enforcement applications, and you’ll find it’s capable of punching through steel plates at the range, so don’t plan on shooting M855 at the gun range.

The M855 round was designed for peak ballistic performance out of a 20" barrel with a 1:9 twist. Originally it wasn’t created to defeat body armor but was meant to penetrate thin barriers such as car doors and steel helmets. It’s also good at bucking the wind at longer distances. The M855 bullet is 0.906" in length and composed of a combination of lead and steel core with a partial copper jacket.

M855 green tip
M193 (left) M855 (right)

What Level Body Armor Stops 5.56 Green Tip?

To defeat the penetrating energy of a 5.56 round, one of the most common rounds in the US, would require, at minimum, Level III body armor, but that’s just standard 5.56, not M855 green tip.

Generally speaking, M855 can penetrate 3 mm of steel at a range of 600 meters. Fortunately, NIJ-Listed Level IV body armor is rated to stop at least 3 shots from an M855A1 round. The NIJ rates Level IV body armor as able to defeat armor-piercing bullets up to .30 caliber. Level IV body armor is going to be more expensive and heavier than Level 3 body armor, but it’s going to afford the best possible protection against M855 green tip ammo.

Military and law enforcement officers typically will wear Level IV body armor for protection against 5.56 rounds including the M855. Not even M855 was designed to penetrate Level IV body armor. Thankfully, law-abiding civilians can buy Level IV armor today.

Level IV AP Plate

at West Coast Armor
Prices accurate at time of writing

Use Code ‘refactortactical15‘ for 15% OFF your order at West Coast Armor!

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