5.56mm fragmentation statistics?

[Doggieman]

Hi, just wondering if anybody has any actual statistics indicating the percentage of time a 5.56 FMJ round will substantially fragment within the body. I've heard a lot of reports saying that they don't fragment nearly as often as people seem to think they do and the result is having to shoot an aggressor several times before he/she drops.

Any hard numbers?

Thx!

 

[Bartholomew Roberts]

Depends on which 5.56mm round you are talking about... IIRC, M193 and M855 both fail to yaw or yaw too late about 25% of the time (and therefore do not fragment). Other military FMJ like Mk262 have very consistent yaw behavior.

 

[Doggieman]

stats for any of the different type of 5.56 rounds, even including .223s, would be great. Anything that's out there!

Thanks again!

 

[Double Naught Spy]

The only "hard" numbers I see repeated consistently pertain to velocity for the M193 rounds at 55 gr. That is, bullets traveling at 2700 fps or greater at impact are in the range that will consistently produce fragmentation. Below 2700 fps at impact, and the frag rate and amount of fragmentation drops off. So you lose a lot of fragmentation potential beyond 100-150 yards when starting with a muzzle velocity of 3100 fps (16-18" barrel).

Of course, that is dealing with what tends to happen, not absolutes.

 

[Byron]

My use of the M193 as a 20 year old infantryman in Nam 68 showed the bullet never failed me.I distances were under 100 yards and many times much closer due to the triple canopy jungle we were in in The Central Highlands. Byron

 

[Doggieman]

The reason I ask is because I remember always hearing about how "lethal" hollow-points were and then read awhile back that they don't expand all that often and hardly ever expand when penetrating heavy clothing first.

So I figured if HPs are unreliable expanders then I have a sneaking suspicion that 5.56s are unreliable fragmenters.

Just seems to me that to expect a bullet to *do something mechanical* (eg. open up or come apart), and do it reliably, when traversing inside the body of a target is expecting a lot. And if it doesn't do it, you've just punched a hole in the bad guy the diameter of a Q-Tip, which often ain't enough.

 

[Bartholomew Roberts]

Just a note; but the numbers I mentioned above were for rounds travelling over the 2700fps frag threshhold. I'd also note that the "fleet yaw*" phenomenon is worse in small caliber rifles like the 5.56mm.

*fleet yaw refers to differences between individual rifles to the degree that one rifle firing the same lot of M855 as another rifle, may fragment consistently at 2500fps while the second rifle will not fragment even at 2800fps. Based on my VERY limited reading, fleet yaw seems to be less relevant with bigger, heavier bullets and match bullets (which are after all designed to be consistent).

There are a lot of good links in the THR Rifle Forum Reading Library tacked to the top of forum on this subject. I would also recommend visiting Tactical Forums and checking out all of the posts by DocGKR.

 

[Deer Hunter]

And I've attached a nice graphic.

 

[Soybomb]

The reason I ask is because I remember always hearing about how "lethal" hollow-points were and then read awhile back that they don't expand all that often and hardly ever expand when penetrating heavy clothing first.

So I figured if HPs are unreliable expanders then I have a sneaking suspicion that 5.56s are unreliable fragmenters.

Don't forget you're talking about 2 very different mechanisms of action here. I think fragmentation is probably a little easier to achieve.

I'd like to see the report that shows that hollow points hardly ever expand. Heavy clothing tests are pretty standard today and the bullets seem to be designed to accomidate it. I believe I've seen a study before showing a pretty good success rate with the round being studied but I don't have that information saved so I can't cite it. It'd be good reading though.

 

[Gearhead Jim]

FWIW, I recently saw some pics from Federal showing the jello blocks after being shot by their various .223 rds.
What surprised me was their 55 gr American Eagle, which should behave like M193. At 2869 fps the round fired into bare jello did fragment, the round fired through "heavy clothing" (not very heavy, IMHO) did not, it just squeezed a small piece of lead out the bottom. But it did tumble and do a huge amount of damage.
The idea that 2700 fps will guarantee fragmentation, seems to be incorrect.

 

[RockyMtnTactical]

Fragmention can be "reliable", but it's still not 100%... There are a lot of factors that play for fragmentation to properly take place... including bullet design/construction (and each one is slightly unique), what it's hitting (clothing can slow down a bullet and send it below the frag threshold), who it's hitting, where it's hitting, how fast it's going...

That said, good shot placement trumps fragmentation 99% of the time, so although fragmentation can help with effectiveness, it's no substitute for shot placement.

 

[Bartholomew Roberts]

The idea that 2700 fps will guarantee fragmentation, seems to be incorrect.

A few things to keep in mind with regard to the 2700fps number:

This is an ammunition specific number (M193 or M855). If you are using different ammo (Wolf 55gr FMJ for example) you will see totally different performance. Different jacket thickness, different methods of manufacture, more complex construction (like M855) all effect how the bullet acts.

Also, there is variation on that number from lot to lot of ammo as well as variation between individual rifles. 2700fps was picked as the velocity range where most M193 and M855 fragmented after yaw. Sometimes it may be lower than this, sometimes it could be higher.

Finally, remember that you have to have yaw before you have fragmentation. If the round doesn't yaw or yaws late, how fast it is travelling doesn't matter much.

 

[johndoe1027]

thanks guys, very informative thread!
Nice chart Deer hunter.

 

[Doggieman]

That said, good shot placement trumps fragmentation 99% of the time, so although fragmentation can help with effectiveness, it's no substitute for shot placement.

True, but shot placement trumps EVERYTHING, ALL the time. Let's face it, if you can always put your first shot in the guy's right eye then you can run around with a .22 short.

The only way this fact is meaningful is if one is saying that 5.56 lends itself to better shot placement than 7.62. And that certainly could be true.

The idea of punching .22 caliber holes in a big man running toward me makes me very nervous, which is why I asked about the stats of (not velocity but) fragmentation numbers. I take it no one's shot, say 50 rounds at 2700+ fps into gelatin and come up with a % of fragmented to non-fragmented.

 

[hagar]

You as a civilian do not have to comply with the Geneva convention. Stick a 60 grain VMax or a 64 grain Winchester power point bullet in your AR15, and forget about yaw and fragmentation, these bullets are much more effective than any fmj.

One of my coyote hunting buddies really annoyed me by insisting on using 55 grain fmj's in his Mini-14, and 9 out of 10 coyotes he shot, ran off like a bat out of hades, and the other one would normally spin around till it dropped or got shot again. Some of the others we tracked down and found dead 100-300 yards away, some we never did. After I gave him a couple of serious lectures about the shortcomings of his bullet, and seeing how coyotes shot with my 22/250 using a 64 gr powerpoint just dropped dead right there, he saw the error of his ways. He started using decent hollow point bullets and his kill ratio improved radically.

 

[Double Naught Spy]

hagar, it sounds like they all probably died, so the kill ratio didn't change, just the speed of death.

I don't think anyone here was worried about the Geneva convention. We are not talking about prisoners of war. Did you mean the Hague convention? It banned hollowpoint use in war.

 

[hagar]

Sorry, meant Hague..

The "speed of death" might be more than a little relevant if your opponent is shooting back at you.

 

[DMK]

Does anyone know of any Ballistic Gel tests of M193 and M855?

Actually, I don't think I've ever seen any of real Mk262 or TAP either.


Never mind, I found some:

http://www.ammo-oracle.com/body.htm#m193orm855

The block of gelatin struck by the SA 1986 M193 round.

 

[DMK]

The reason I ask is because I remember always hearing about how "lethal" hollow-points were and then read awhile back that they don't expand all that often and hardly ever expand when penetrating heavy clothing first.

Good point, but as Soybomb indicated above it a different mechanism. An HP relies on hydraulic pressure to open up the tip making it act like a larger round. FMJ or HPBT rifle rounds will pierce through clothing or even soft armor, then when they enter the body they start to tumble. Some lighter rounds cannot handle the stress of this and break apart.

So I figured if HPs are unreliable expanders then I have a sneaking suspicion that 5.56s are unreliable fragmenters.

Just seems to me that to expect a bullet to *do something mechanical* (eg. open up or come apart), and do it reliably, when traversing inside the body of a target is expecting a lot. And if it doesn't do it, you've just punched a hole in the bad guy the diameter of a Q-Tip, which often ain't enough.

Another good point. The loss of structural integrity (fragmentation) was mostly accidental. Lightweight bullets just happened to "come apart" when hitting squishy objects at high velocities. It's a balancing act of a very fragile bullet that fragments early (varmint rounds) or heavier bullets that fragment late enough and retain enough mass for deep penetration. Now we've come to depend on this, but most anti-personnel rounds designed today use bullets that were actually designed for other purposes (Match rounds mostly) and happen to fragment when pushed fast enough.

 

[DMK]

FWIW, I recently saw some pics from Federal showing the jello blocks after being shot by their various .223 rds.
What surprised me was their 55 gr American Eagle, which should behave like M193. At 2869 fps the round fired into bare jello did fragment, the round fired through "heavy clothing" (not very heavy, IMHO) did not, it just squeezed a small piece of lead out the bottom. But it did tumble and do a huge amount of damage.
The idea that 2700 fps will guarantee fragmentation, seems to be incorrect.

While velocity is a factor, it's only part of the equation. Most commercial .223 FMJ rounds are of heavier construction than M193 and few have a cannelure near the middle which is said to be a weak point. Since the bullet itself is not as fragile, it won't fragment consistently if at all.

 

[Larryect]

Has anyone tested the 55 gr Winchester bulk pack bullets with the cannelure, sold for reloading?

 

[Doggieman]

One of my coyote hunting buddies really annoyed me by insisting on using 55 grain fmj's in his Mini-14, and 9 out of 10 coyotes he shot, ran off like a bat out of hades, and the other one would normally spin around till it dropped or got shot again. Some of the others we tracked down and found dead 100-300 yards away, some we never did. After I gave him a couple of serious lectures about the shortcomings of his bullet, and seeing how coyotes shot with my 22/250 using a 64 gr powerpoint just dropped dead right there, he saw the error of his ways. He started using decent hollow point bullets and his kill ratio improved radically.

That unfortunately doesn't say a whole lot for the 5.56 round. I'm looking for a SHTF round that will reliably take down bad guys who are coming at me or my family. Eg. 7.62