M855 – Beyond the Hype

M855 – Much Ado About Nothing?m855

This is a guest post by Andrew Betts

The BATFE furiously backpedaled after initially indicating they had decided that M855 or SS109 type 62 gr FMJ 5.56mm ammunition met the definition of an armor piercing projectile. That such a decision would have been patently ridiculous apparently had no bearing on either of their decisions. For it to be considered as armor piercing under United States Code, the projectile would have had to been made “entirely” of a material other than lead and M855 is constructed of three different materials. It has a lead core, a copper jacket, and a small steel cone inside the jacket on top of the lead core.

There have been a multitude of articles written about the BATFE’s decisions over the past few weeks, though. This article will focus on the performance of M855 ammunition.

Let us address that elephant in the room first. Does M855 penetrate armor any better than M193 55 gr ball or other 5.56mm or .223 cal ammunition? It is widely known that almost any rifle ammunition will defeat soft body armor (threat levels IIA, II, and IIIA). What is not widely known is that plain, vanilla M193 can defeat level III steel armor at close range.

The big take away from that test is that M855 did not penetrate the armor, while M193 did. There may very well be certain obstacles that M855 can penetrate better but when it comes to actual armor that a real person might wear, m855 2that does not appear to be the case. Soft armor will always be penetrated by any .223 or 5.56mm.

Conversely, level IV ceramic plates will stop any .223 or 5.56mm. In the only case where there is actually any difference, M855 actually performed more poorly. In other words, it is pretty terrible “armor piercing” ammunition.

How does M855 perform in tissue, though? Does the three part construction contribute to fragmentation? Getting shot with any 5.56mm will ruin your whole day, but does M855 perform well enough in tissue to choose it over other .223/5.56mm loads for home defense?

So it did fragment and it did cause significant tissue damage, but how does that compare to other .223/5.56mm loads? The “neck” length of a wound is the length of wound channel before the projectile begins to expand, yaw, or fragment and disrupt more tissue it is where the wound channel widens. In this case, that happened at about 4.5”.

Medium weight soft points or heavy OTMs that are more commonly recommended for defensive use tend to have a neck length of less than one inch. M193 also tends to have a slightly shorter neck length. Despite the long neck length, upset did occur early enough to cause significant damage to vital organs. Penetration was nearly ideal and the amount of fragmentation was pretty substantial. The bottom line was that in this test, M855 performed adequately but did not particularly excel.

Unfortunately, the whole story of the performance ability of M855 cannot be told by one test shot. Because of the construction of M855, its ability to wound is dependent entirely on its ability to fragment, which is in turn dependent entirely on velocity. To make matters worse, the complicated construction of the bullet makes it somewhat erratic in performance. If you really want to go down the rabbit hole, Google “fleet yaw”.m855 3

Does M855 do anything really well, though? It is cheap. Or at least, it was cheap before the BATFE decided to muck up the supply/demand balance. It will likely be even cheaper soon as people try to unload ammunition that they never really wanted in the first place. It is reliable.

M855 is true NATO spec 5.56mm ammunition at true 5.56mm pressure. That means that rifles that may be finicky with lower pressure .223 Rem ammunition will often function perfectly with M855. It is generally about 3-4 MOA, which is accurate enough for plinking or the zombie apocalypse but it is certainly not Camp Perry accurate. M855 also has a sealed case mouth and primer pocket and has a crimped primer. All of these factors make it a solid choice for plinking, training, short range competition, and long term “just in case” storage.


Andrew Betts served with the Arizona National Guard for over 12 years, including a tour to Afghanistan. Visit his YouTube Channel for more great shooting information.

Photo credit – Andrew Betts

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