In order to avoid making yet another thread go way off track, I'm starting this thread.

Current production M855 bullets' steel inserts have NO hardening; if they were hardened, they would not be easily sectioned, as ARFCOM member wolfganggross and others have done.

(from the ARFCOM ammo project) L -> R: IMI, Bosnian "black tip", LC M855, and "Tungsten Molly coated M855? Watch what you by on line!"
Note that wolfganggross points out the steel element in these bullets is Rockwell hardness C 40-45 and made from C 1045 carbon steel, while "real" AP ammo such as the .30-'06 M2 AP bullet has a steel core with a RHC of 65 - much harder, and the M993 7.62 AP round has a tungsten core.

The MIL-SPEC for M855 ammunition (MIL-C-63989C(AR)) calls for the following:
There is nothing about penetrating hardened materials, body armor, multiple layers of metal plate, etc., just a steel plate that is a stand in for a "standard NATO helmet" as discussed elsewhere.  E. C. Ezell, late curator of the Smithsonian's Division of Armed Forces history, National Museum of American History, in his Small Arms today, (1984, Stackpole Books), included information from FN's military catalog about the SS109 with FN's test standards, which were essentially the same:
 This essentially became the NATO standard (unfortunately I cannot locate a STANAG to post to support this) for the 5.56mm NATO round. Please note that FN calls it a "ball projectile."

This leads to the conclusion that M855 bullets are made with a non-hardened (mild) steel filler in the nose.  Most texts still call this a "penetrator" (even Army texts), but it is not like an AP bullet's penetrator component in that it is neither pointed nor hardened.  It appears that this component is there to a) move the center of mass rearward, which improved the gyroscopic stability of the bullet over longer distances and b) to help it maintain its shape during feeding, firing and impact.

While it may be called a "penetrator" it appears that the steel insert is not a classic AP component, and while it facilitates better penetration over longer distances, this can be attributed to straighter flight over those distances, and an increased likelihood that the bullet will impact point-first, and thus concentrate its kinetic energy at that point of impact for more effective penetration.

I assert that marketers attempt to get the buying public to believe that they are buying something other than a "ball" round that simply goes straight for longer distances, and that the M855 is mischaracterized as being "more than just a ball round."

So flame on if you wish, but that's what I've posted in several other threads and gotten trashed for...

October 1980





STANAG 4172 - Adoption of 5.56





STANAG 4179 - Adoption of the M-16 compatible magazine



ETA: Your assertions are spot on.
 

Good stuff but stupid people are stupid. Most people don't understand basic math, physics, or chemistry, so using facts on them is a waste. You need sensationalism and hearsay to make the ADD society we have pay attention.
The new SS-109 cartridge propels a heavier 62-grain semi-armor piercing
projectile at an initial velocity of 3,050 fps (924 mps).  The improved
projectile contains a 10-grain .182 caliber hardened steel penetrator
that ensures penetration at longer ranges.






you're competing against the ammo oracle as well
 

I don't see what your telling us to be anything different than what most of us already know.  Of course it's not true armor piercing. I haven't seen it advertised as such. I have seen it advertised as a penetrator which IMO it is. It does penetrate mild steel

better than regular ball ammo. Ball ammo it is not, armor piercing it isn't either. However, I wouldn't have people believe this is the same "ball ammo" that the M193 is because it's not.

I've shot true ball M193 ammo at ar500 steel at 25 yards and it flies apart leaving nothing more than a bare spot where the paint was.  M855 ammo at 25 yards won't penetrate it like true armor piercing will but it leaves a good dent. Much more damage than the ball M193.

My disassembly and "testing" of the M855  insert  took place in the early 1990s; the projectile may have been made in the 1980s. The insert in the tip of the bullet was a hard, shiny cone with a sharp tip and about 1/8" tall when sitting on its base. If someone has disassembled a current production M855 projectile and found a mild steel insert then so be it.

I believe the "penetrator" is a bit harder then your average mild steel.

1045 is not defined as mild steel.  Too much carbon.

But 1045 is also not "hard," either.  The point is obviously that even if it is called a penetrator, it is neither hardened nor of a material that can by itself be considered hard enough to punch through hardened steel.  Using the terminology "penetrator" makes it sound like the steel insert allows the bullet to defeat hard targets.  By design it is supposed to defeat steel helmets, and history shows that the M855 doesn't defeat auto windshields too well, let alone hard targets.
The M855 was type classified and fielded in the early 1980s, and there have been no significant changes to the spec for the bullet since then.  I have never seen any official information suggesting that the steel insert was anything but a metal filler to move the mass of the bullet farther back while preserving the shape of the bullet's ogive.  I have seen examples of intentionally armor piercing 5.56mm bullets that had hardened inserts, but they were not M855 bullets.  It does not take hardened materials to punch through 3.5mm of 1010 or 1020 steel, just a 50-65gr projectile that can strike the target point on.  M193 bullets can do that at 600m, but not consistently, due to their tendency to yaw as they lose gyroscopic stability, which was exactly why the FN engineers went with a longer bullet with a center of mass that was far enough aft to allow the bullet to remain stabilized for longer flight times/distances.

If the "penetrator" doesnt do anything, then why does M855 penetrate twice as deep in pieces of metal that I have shot, when comparing to M193?

I ridn't say it did nothing; quite the opposite,  I specifically stated that it helps the bullet maintain the ogive shape on impact.  This is a major part of its improved performance.  But it can't do that part if the bullet hits at a 45 degree angle...  First, the bullet has to strike the target point first, then retain its shape for the improved penetration you noted.  The M193 bullet loses a lot of energy in deforming on impact with hard targets, reducing its ability to punch through,

But again, the penetrator insert is not anything magical.  A lot of African hunting bullets manage this with very heavy jacket tips.  The steel insert both assists maintaining shape AND moves the center of mass backward, which allows that stronger tip to concentrate the bulletx's kinetic energy on the smallest possible point.

F=M*A



The 193 will do better close up, the 855 will do better long range. Its been posted/argued/whipped to death before.

Thats what everyone tells me, but even at 50 yards M855 penetrated twice as much, yet people keep repeating that at short distances like 50 yards M193 is better.

It is better against people. The SS-109/M-855 bullet cannot compare to a true AP bullet.



The SS-109 bullet was designed so that the melplat would stay forward and meet the 600M NATO test, as well as penetrate the WG Army Steel Helmet. LC got rid of the small steel tip on the steel insert years ago so they could speed up production. In testing they found out that this tip (which AFAIK is still on the NATO SS-109 load) contributed nothing to bullet performance.



 

What I keep reading people post is how M193 is better against hard targets at closer range.

Also, the whole "M193 is better on people" is a bunch of BS too.

DocGKR posted this as his view of M193.


In my experience it falls short too..

The bullet did not fragment, that it why the wound was not that impressive. If the M-855 does not fragment, it is not impressive either. Since neither bullet is designed to fragment, the variable fragmentation performance of both bullets means that one should not depend upon fragmentation as a reliable wounding mechanism.



Also, 12_gauge did testing here a few years ago that showed PMC M-193 ammo would not penetrate steel at close range, but Winchester Q3131 would.



 

Not what I have shot, at about 75 to 100yds (max) M193 will cut through some metal where 62 won't. If youre talking denting it, yeah 62 will leave a bigger dent/potmark. The other side to this is the metal type is critical. Lots of confusion on what types of metal are being used.

Well, the penetrator is hardened, it is just not AP.  I think that has always been clear, but maybe some folks don't get it.

Hard as in Rockwell C 45-50...that's about as hard as an axe head, and substantially less hard than a knife blade (read about that here).  Since the RHC scale goes to a theoretical infinite hardness of 100, comparing an item of RHC 45 with one of 65 (the M2 AP penetrator), you can see that the scale is hardly linear...45-50 is a LOT softer than 65.  This level of hardness does, however, allows the insert to maintain shape during penetration.

Associating "hardened" anything in a bullet implies that the bullet is armor defeating in some way.  The M855 bullet punches through LIGHT steel because it strikes point first and maintains its shape during penetration...and still won't defeat US windshield glass reliably...  Real AP will go through that glass, and a lot more.  So yes, the insert is hardened, but so is the stingless steel back cover on your watch.  It has to be to withstand manufacturing and penetration. But it is NOT an armor piercing component, and I think it is essential that the shooting community separate bullets like this from the concept of armor piercing bullets.

I know that the standard M2 ball ammo with a .30 caliber 150gr FMJ bullet will penetrate steel- up to a point. It isn't AP but it hits point first. We have been told, repeatedly, to not shoot the steel swingers with our Garands at my club.

You don't believe me? Look at the comment that drove off Molon and others that used to post here. Most retards argue with their feelings and not facts.



 

Was that the BS buster thread? Molon has spent the last year or so divesting himself of a lot of AR gear.



 

Deleted

No kidding? The mild steel reference was a reply to another thread in which a poster claimed that the M855 penetrator tip is mild steel. I'm sorry for the attempted cross pollination of similar threads

It seems to me that people really just want to know what kind of steel is used in the penetrator tip. It is harder than mild steel (at least my LC XM855's as of 2010 are). Simple reason I can say this, I was shooting mild steel, I went around and picked up the tips (undamaged) at the base of the targets. Takes a steel of equal hardness or greater to damage steel…and the tips were undamaged. If you really want to figure out what steel is in those penetrators, spark test and compare to the spark tests of different types of steel.

From the first post:



"Note that wolfganggross points out the steel element in these bullets is
Rockwell hardness C 40-45 and made from C 1045 carbon steel, while
"real" AP ammo such as the .30-'06 M2 AP bullet has a steel core with a
RHC of 65 - much harder, and the M993 7.62 AP round has a tungsten core"


 

You're busting people balls for being bad at math, but it looks to me like you are trying to say that 3050 fps is equivelant to 924 mps. Unless the 924 thing is something else...

Off-topic comments removed - Eric802

I get around 930mps.

While I was doing math problems in my sleep last night I realized mps is meters per second, not miles per second.

Yes, 924 mps is ~3,031 fps.