InRange TV On The M855 Round

In response to the ongoing dustup over M855 ammunition, Ian and Karl of InRange TV have done a short video explaining some basics about the round, and its capabilities. As host website Full30 does not allow videos to be embedded on other websites, readers will have to follow the hyperlink to watch the video.

The basic points that M855 is neither a magical armor penetrator, nor is exceptionally effective from a terminal ballistics standpoint – and a brief demonstration of the round’s limited accuracy potential are all well-made, but there are a few statements that Ian makes in the video that I feel either need clarification or that are a little too strongly argued.

The first is that M855 was designed specifically to penetrate a Russian helmet at 600 meters, and that this was an unrealistic target for soldiers armed with M16’s – this is true, but a little misleading. Fabrique Nationale’s SS109 – the parent type of M855 – was intended to provide an adequate ball round that could also be used in the new squad-level automatic rifle – the FN Minimi which would enter US service as the M249 SAW, while retaining the positive characteristics of M193. The simplest way to accomplish this was simply to lengthen the bullet jacket, change the tangent ogive to a secant ogive with a much finer meplat (both improving the form factor of the projectile and thus its ballistic coefficient), and to add a small conical steel insert to the front. This insert wasn’t a true armor penetrating core, but was simply designed to breech the helmet, allowing the rest of the bullet mass through and causing a fatality. While aiming for individual helmets was totally unrealistic – even for the fully automatic M249 SAW, a round that couldn’t penetrate a standard enemy helmet and produce a casualty at what was supposed to be its effective range would not be suitable for military service. So, whatever the consequences, SS109 won the competition and it was assumed the positive characteristics of M193 would be retained. The takeaway here should be that while the deciding characteristic of what would become 5.56×45 NATO was how well it penetrated a Soviet helmet at 600m, it is not a specialized armor penetrator like rounds such as the 5.8x42mm DBP-10, 5.45x39mm 7N22, or .30 M2 AP. However good or bad the design, it was intended as a general-purpose round, suitable for both soft and hard targets.

The requirement for a 1:7 twist is our second clarification: This was not necessitated by the 62gr SS109/M855 bullet, but rather by the much, much longer 64gr M856 tracer. The tracer projectile is longer even than M855A1 or Mk. 262, which is why a twist rate change is not necessary for use of either of those rounds. The M855 bullet itself can be stabilized sufficiently under temperate conditions by twist rates as relaxed as 1:10.

Ian makes a few statements regarding M855’s lethality that I think are also worth addressing. The below quote is taken from the video’s description:

Frankly, M855 is probably the worst military-issue 5.56mm ball ammo ever made.

The original 55 grain M193 ball had a tendency to tumble in the body and make effective wounds. The new Mk262 77 grain ball also destabilizes quickly, and has much better long-range energy retention than the M193. The M855 was designed to poke holes in Russian helmets in the Fulda Gap, and offers poor wounding ability and poor accuracy.

The initial statement in particular ignores the initial ammunition issued under the designation “M193”, before case hardness specifications were laid down. The lack of case hardness specifications resulted in problematic extraction, exacerbating an already bad situation. Further, M193 was never held to a high standard for accuracy, either, so making that comparison is a little uneven.

In the video, Ian says more:

When it comes to ballistic effect, this is an area of significant problem with the 855. Because it was designed to penetrate Russian armor, it doesn’t really do anything when it hits a medium like a human. What you get is frankly what happened in Mogadishu, if you watch Black Hawk Down you saw the effect; it pokes little holes, it does not destabilize when it goes through a person. So as a result it doesn’t have a whole lot of terminal effect.

To say that it “doesn’t destabilize” when it hits a person is incorrect. What needs to be understood is that the results of gunshots even under similar conditions are highly variable. M855 certainly has the capability to make grievous wounds through fragmentation – it is, after all a fairly close relative to M193, sharing its boattail, materials, jacket thickness, and cannelure. So where does the reputation for its poor terminal effect come from; what’s the science behind through-and-through wounds, and is M855 especially prone to that outcome relative to other 5.56mm FMJ types?

A complete answer to this question is beyond my level of expertise, but there are a couple possibilities. First, the fleet yaw problem necessarily means M855 will have highly variable results at close range. Beyond close range, the 1:7 twist rate could be causing a reduced angle of precession, and therefore possibly a lower likelihood of early yaw and fragmentation.

One other possibility is that the steel insert is supporting the nose of the jacket enough to preclude the possibility for yaw-less fragmentation. I have no direct evidence that M193 is capable of head-on fragmentation, but there are some supporting anecdotes of early 5.56mm impacts on extremities that resulted in grievous wounds, which could have been caused by yaw-less fragmentation. If it were proven that M193 was capable of yaw-less fragmentation, and that the steel insert in M855 reinforced the jacket enough to preclude that possibility, that could be an explanation for M855’s perceived low effectiveness. However, further studies of the probabilities of different outcomes for both M855 and M193 strikes would need to be conducted to fully confirm this theory.

What is clear is that while it’s not a certainty that M855 will produce through-and-through wounds – which is no help to those who have had the round fail on them in combat, it is true that the round has been found lacking in Army use. This desire for a more effective round led directly to the development of both the Mk. 318 and M855A1 rounds.

Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He is also the author of the original web serial Heartblood, which is being updated and edited regularly. He can be reached via email at


  • iksnilol

    From what I know if you hit the extremities in the bone, then the bone will shatter causing nasty wounds.

    • James

      I don’t think there exists a 5.56 in common usage (gotta hedge my bets against crazy wildcat loadings) that wouldn’t shatter bone when hitting an extremity.

      • iksnilol

        Supersonic bullets in general shatter bone. I wasn’t thinking about 5.56 specifically.

  • Cal.Bar

    All of these discussions miss the point. Droning on about how the round is poor at this or that is irrelevant. (BTW, if it’s such a POOR round why are we all complaining about it being banned.) The fact is that the CORRECT argument is a dry and boring legal one as to whether the round is in fact a “pistol round” merely b/c a few AR pistols are floating around (after all, there are custom pistols of one sort or another chambered in most rifle calibers) and/or whether the round is or is not “armor piercing” if that can even be defined from a legal standpoint.

    • Wayne Cummins

      People are complaining because the government should have no authority to ban any type of ammunition.

  • Lance

    Good article. Its seems that M-193 still has a edge in urban combat against none body armored foes. Iraq vets wanted M-193 55gr ammo alot more than green tip ammo. Though the USMC looked at this and made a solution with Mk-318 ammo. It also doesn’t have as dirty of a powder and higher pressure as Army M-855A1 ammo.

  • Chris

    way to have balls firearm blog, delete on point comments.

  • Rob

    I have never had a purpose for M-855. That said I like having lots of cheaply priced ammo on the market to keep prices in general down. It is also more than adequate for plinking and if it was cheap enough I would use it for that. Right now I use steel case for plinking. It was starting to look like the move to 855A1 was going to make large amounts of surplus 855 available in the market. That is what I see as the real problem – the government using fiat regulation to make ammunition artificially more expensive.

    • Miles

      And you have what I believe is part of the reason the ATF made this decision now.
      With M855A1 online and replacing M855, our fearful leader decided that Lake City was producing to much for civilian consumption.

      • Ethan

        That’s the key – the market is about to be FLOODED with surplus M885 as it becomes ‘obsolete’. We’re talking HUNDREDS of MILLIONS of rounds. Ammo prices will hit the basement floor and go deeper… unless of course it all becomes conveniently “illegal”.

    • n0truscotsman

      Yeah I agree too.

      I’ve never bothered with M855 simply because there are so many better cartridges for plinking and self-defense out there.

      -Steel case is cheap and works with respectable reliability in my 223-caliber rifles. But I still use 55 grain fmj brass cased for plinking, which is still cheaper than M855, in my ARs.

      -For “combat” or “self defense” purposes, prvi partizan 75 gr or Wolf Gold in bulk, or CBC 77 gr. Or 50 gr TSX. All of which blow M855 out of the water in terms of ballistic attributes and accuracy.

      But if green tip tickles someone’s fancy, then by all means, I support their right to buy it and oppose the stupidity behind any attempt to ban it.

  • John

    By the way, has there ever been an attempt at a tumbling 5.56 round like the 5.45? Just wondering.

    • Heretical Politik

      All spitzer fmj rifle bullets tumble. its a function of the base of the bullet having greater mass to surface area ratio than the tip. It’s just a question of how soon do they begin to tumble. The M193 starts tumbling fairly quickly whereas the M855 travels further after impact before it begins to tumble. The complaint with M855 is that with enemy combatants with slim or malnourished bodies, there is a chance that the bullet will not yaw before it has exited the body, resulting in minimal tissue damage. Reports from Vietnam about the wounding effect of M193, on the other hand, were pretty horrific.

  • Ethan

    SS109 / M885 IS:
    -Average at penetrating
    -Outperformed by XM193 in almost every way, including penetration.
    -NOT Armor piercing as defined by US Code – as evidenced by
    1 – “Armor piercing ammo” must be greater than .22 in size. M885 is not greater than .22.
    2 – “Armor piercing ammo” must have a core of mostly of Steel, tungsteen, etc. – The steel tip on M885 is 25% Steel of the total weight – so 75% of the bullet is NOT steel.
    -Fully suitable for sporting purposes, not that has ANY bearing on its Constitutional legality.

    -Fully protected by the 2nd Amendment to the U.S. Constitution.

    • Miles

      First Ethan, read and understand the complete, statute, not the incorrectly edited one you posted.


      (B) The term “armor piercing ammunition” means—

      (i) a projectile or projectile core which 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

      (ii) 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.
      AP ammunition can be of any caliber. Sorry.

      ATF is ‘hanging their hat’ on a lawyerly parsing of the statute.

      The M855/SS109 bullet has a “core” (as in, they consider that the bullet has 2 cores, one lead, the other steel) that it steel. It is a ‘core’, not a ‘tip’ which I think, that if the ATF can parse words this fine, others should too. Since M855A1’s penetrator is a ‘tip’ not a core and the core is simple copper, we should have XM855A1 ammunition available.

      Any reasonable person would consider ” a core ” to mean the whole core, but this is what you get when a law is written is such a way that a law shark can twist words to mean something else from what was meant.
      Also, we may have an argument using the Heller v D.C. decision to hang our side’s hat on a 2nd Amendment issue.
      We have two groups to blame. Congress is in this as far up to their necks as the ATF is.

      • Ethan

        I’m not following – “Larger than .22 caliber” does not accurately describe .223REM/5.56NATO. That is .22. If you go out to three decimals .224 still will accurately round to .22.

        Otherwise I agree.

        Also “intended for use in a handgun” definitely is not true. Its like the ATF was trying to fail every single clause of this document..

        • Miles

          The last word in “i” is *or*. This means that the projectile is defined as AP by either of “i” or “ii”. It doesn’t have to meet the definition of both.
          If it meets one or the other, the projectile, by the statute, is AP.
          Like I said, ATF is parsing the statute to make it read as broadly as possible.

          • Ethan

            Gotcha.. thanks for explaining to the slow kid :-P.
            Man, they are slick. But it still fails the definition – its not larger than 22 caliber and its not entirely made of exotic metals.

          • Mark N.

            You are still mixing up (i) and (ii). The “larger than .22” is part of (ii), but not (i), and applies only to a projectile where the jacket is greater than 25% of the total weight. I’ve read that this was intended to ban a particular Swedish branded 9mm ball round that had a very thick jacket that would go through a ballistic vest “like butta.” The M855 is neither “larger than .22 caliber” nor is its jacket more than 25% of the bullet’s weight. Thus part (ii) of the definition is irrelevant to the ATF proposed ban, which relies entirely on the language of section (i).

          • Ethan

            Right – but neither (i) NOR (ii) applies to M885. That’s what I was trying to communicate.

            They set it up so either (i) , or (ii) must be true, and for M885 neither (i) nor (ii) is true.

          • Miles

            We agree.
            But unless ATF rescinds their definition of M855 as AP, the Attorney General finds that it has a sporting use exemption (*hah*), our congresscritterz change the law and it’s not vetoed (again *hah*, we’ll have to wait for Jan 21 2017 for that), or a court case is decided in our favor, we’re stuck.
            Like I previously posted, with this definition, we may have ATF over a barrel and get M855A1 overruns out of LC. (It’s serve them right)

  • Hank

    Sorry. I was distracted by the VW Thing…

  • Brian M

    I’m sorry but wasn’t this supposed to be an examination of the M855 and whether or not it can be banned by the ATF?

  • The primary clue that FN didn’t consider the SS109 to be armor-piercing should be the fact that they once offered the companion P112 AP round.

  • Swarf

    I… I just want the VW Thing. Like, a lot.

  • This article is regarding the technical aspects of M855.

  • Ethan

    Wrong website. Read the banner at the top of the page.

  • nadnerbus

    The Truth About Guns would be glad to have this comment.

    • n0truscotsman

      Okay thats just funny 😀

  • Tom

    The Marines want to phase out green tip and adopt SOST ammo. I never buy Military ammo. I am only interested in accurate ammo.. and small groups.. M855 is only popular because it’s cheap. Commercial ammo manufactures are ripping off the public by charging ridiculous prices for their products.

  • Uniform223

    I watched the video and found it alittle funny that US troops in Iraq and Afghanistan would clear rooms with the M9. That made me remember battle buddy of mine who confirmed what he said but for another reason. When he was in Iraq, the local populace feared the a pistol more than a rifle or carbine because back when Saddam was in power, anyone in uniform who came into your house with a pistol often meant immediate execution.

    • CommonSense23

      Anybody who decided to use a pistol over a rifle for room clearing is a idiot.

      • Ethan

        You’re dissing most of our Marines, but hey, you must know better.

        • CommonSense23

          Most of our Marines? Curious how many marines get to carry a M9 these days.
          And yeah I would say I do. Let’s carry a gun that is harder to shoot in any situation, has less capacity, slower to fire, and no optics. And lets compare that to a guy who is going to have a AK.

          • Ethan

            I can’t tell you why, all I can tell you is that they choose to based on their combat experience. Have some respect.

      • Uniform223

        I believe you missed the point.

  • Pete Sheppard

    Good article, Nathaniel; thanks!

  • The higher velocity of M193 causes wonky effects at close range.

    I agree that in general it’s the better round for rifle work, but SS109 was designed for the SAW while compromising as few of the good attributes of M193 as possible.

    For self-defense, PMC XP193 is excellent ammunition for the money.