Do 5.56 fmj often break up when they hit flesh or water?

Roberts specifically mentions the work done by Martin Fackler and his work with the IWBA and the Wound Ballistics Laboratory at the Letterman Army Institute of Research. Roberts says the best source of information on wound ballistics today for both the military and law enforcement is the FBI.

Roberts does mention a lot of wasted research dollars such as the failed XM25 project which he thought was ridiculous.

Bullets designed to wound based upon yaw and tumbling get mentioned. The legal limitations placed on military ammunition get mentioned.

Why 10% ordinance gel is the best tissue analog is explained.

Roberts talks about the problem of not having enough MDs involved in wounding research today and how that causes issues with a lack of understanding of anatomy and physiology in places doing research such as Aberdeen. Start at one hour and 26 minutes to hear about that and why we should be getting information on wound ballistics today from the FBI and not the Army.

To hear about military rifle ammo, start around one hour and 37 minutes.
 
Roberts talks about the problem of not having enough MDs involved in wounding research today and how that causes issues with a lack of understanding of anatomy and physiology in places doing research such as Aberdeen. Start at one hour and 26 minutes to hear about that
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I think you are hearing what you wish to hear. He talks about events that occurred in the late 80's and early 90's. Your confusing that with events Post 9-11 and changes made. That is one of the lessons' learned that came out after 9/11 in the processes. Infact, involving non-engineers, Government Resources, The Private sector, and end user's was a rectified and one of the biggest programs enacted. We regularly interfaced with cutting edge research on the civilian side and there is a whole section in SOCOM whose entire job is to capture emerging technology.

That has nothing to with the fact:

ONLY Aberdeen has the equipment to measure bullet positional data in real time.

wound ballistics today from the FBI and not the Army.
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Again, I think you are misinterpreting what he says. The FBI does the wound analysis for The Department of Defense. Wound analysis is NOT ballistics, it is Wound Analysis.

All of the DoD Wound Analysis is the FBI Wound Analysis. There is no conflict between them. In fact, the FBI deployed with us and manned a section at the CJSOF/SOTF level. That section was the boots on the ground for this and other things that made up the FBI's integration with SOCOM.

Why 10% ordinance gel is the best tissue analog is explained.
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The limitations of GEL testing are what came out of the cooperation between Government Interagency and Private Sector Dr Roberts is discussing. That is actually discussed in Small Arms Committee Paper on 5.56mm lethality.

He says nothing that changes anything in our previous conversations. In fact, he validates it. We did go to outside agencies to test 6.8 and many other innovations. That does not mean that Aberdeen or the Army was ignored, invalidated, or diminished. Once again, there is no other organization with the equipment to measure bullet positional data in real time outside of the Aberdeen. The lessons' learned and results of all things Dr Roberts is discussing are seen today in M855A1.
 
I think you are hearing what you wish to hear.
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Someone is.


He talks about events that occurred in the late 80's and early 90's. Your confusing that with events Post 9-11 and changes made. That is one of the lessons' learned that came out after 9/11 in the processes.
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Roberts specifically talks about the loss of institutional knowledge after 9/11.

Again, I think you are misinterpreting what he says. The FBI does the wound analysis for The Department of Defense. Wound analysis is NOT ballistics, it is Wound Analysis.
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There are three parts of ballistics. Internal ballistics, external ballistics, and terminal ballistics. Internal ballistics would involve things like chamber pressure, how fast the projectile leaves the barrel, and etc. External ballistics would involve the projectile's flight through the air with things like BC being important. Terminal ballistics involve what happens when the projectile hits the target. Wounding ballistics is a subset of terminal ballistics which studies what happens when a projectile hits tissue. Fackler, who is mentioned extensively in the video, founded the IWBA which is the International Wound Ballistics Association. I'm not misinterpreting what Roberts says in the video.

ONLY Aberdeen has the equipment to measure bullet positional data in real time.
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While that is dandy, I don't think it's relevant for measuring wound ballistics. It might be important in yaw dependent bullets but Fackler had already worked that out before 9/11: https://thinlineweapons.com/IWBA/2001-Vol5No2.pdf
and the civilian world, including law enforement, has had access to bullets that are not yaw depedent for decades.


He says nothing that changes anything in our previous conversations. In fact, he validates it. We did go to outside agencies to test 6.8 and many other innovations. That does not mean that Aberdeen or the Army was ignored, invalidated, or diminished. Once again, there is no other organization with the equipment to measure bullet positional data in real time outside of the Aberdeen. The lessons' learned and results of all things Dr Roberts is discussing are seen today in M855A1.
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Roberts has specific recommendations for 5.56 ammunition for law enforcement and defensive use by civilians and none are military ball rounds. Apparently, he thinks there are measurably better rounds than M855 and have been for years.
 
I don't claim to be an expert, but it is my understanding that impact velocity is what matters. The Vietnam era M16's with 20" barrels would impact fast enough at relatively close range to cause bullets to tumble after impact. Some would break up because they were tumbling, but even those that didn't break up would do more damage than a round that went straight through.

At longer ranges after impact velocity dropped below a certain level the bullets would neither break up nor tumble. And as barrels got shorter the ranges where impact velocity was too slow became shorter.
 
velocity is what matters.
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Of course in older bullet designs be they FMJ or Hollow Point. It is yaw combined with penetration and the ability to induce yaw that causes the most damage.

Hollow points induce yaw at a lower velocity but penetrate less while FMJ penetrates more with more energy required to induce yaw.

M855A1 was designed with lesson's learned from being able to actually measure bullet position in flight.

If you ignore the rhetoric of the article and look at the data:

You will see the M855A1 produced a wound cavity that is 27.56 cubic inches larger than the M855 and penetrated 152.3% farther into the gel block.

That means it made a much larger wound cavity due to yaw AND delivered much better penetration.

https://smallarmssolutions.com/home/the-m855a1

The statement about M855A1 being "not yaw dependent" is very misleading. M855A1 is designed from the drawing board forward TO yaw based upon actual data measured of bullet position in flight. It is engineered with the fact bullets do change position in flight which very much effects the yaw of previous bullet designs. M855A1 will yaw appropriately now matter what position the bullet is in when it strikes the target and therefore is "not yaw dependant".

It's hard to argue institutional knowledge has been "lost" in the Department of Defense when the end result is the mass production of a bullet specifically designed upon the latest research and experience on the battlefield.

That has nothing to do with institutional knowledge being lost or ignored in the civilian sector for your hometown Police Department where they just might be relying upon youtubers shooting a pot roast in their backyard.
 
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I read his statement to mean the projectile will perform as expected in producing the wound channel regardless of the attitude of the projectile upon striking the target. I could be wrong tho.
 
Yep. When folks, including the Army, say a bullet is yaw dependent for performance on soft tissue, they are talking about the slight variations in yaw during the flight of the bullet and how the attitude of the bullet when it hits matters.

Here is the Army talking about it with respect to the M855a1 round in comparison to the M855 and M80 rounds:

The Army tackled the consistency issue by focusing on the yaw of a projectile and how differences in yaw can influence results when striking soft targets. The M855 round, similar to the Army's M80 (7.62mm ball round), is a "yaw-dependent" bullet. As any bullet travels along its trajectory, it "wobbles" in both pitch and yaw, causing the projectile to strike its target at different attitudes with virtually every shot.

For a yaw-dependent bullet such as the M855 or M80, this results in varying performance, depending upon where in the yaw/pitch cycle the bullet strikes its target. For example, at a high angle of yaw, the M855 performs very well, transferring its energy to the target in short order. At a low angle of yaw, however, the bullet reacts more slowly, causing the inconsistent effects observed in the field.

The M855A1 is not yaw-dependent. Like any other bullet, it "wobbles" along its trajectory. However, the EPR provides the same effects when striking its target, regardless of the angle of yaw. This means the EPR provides the same desired effects every time, whether in close combat situations or longer engagements. In fact, the U.S. Army Research Laboratory (ARL) verified through live-fire tests against soft targets that, on average, the M855A1 surpassed the M80 7.62mm round. The 7.62mm, although a larger caliber, suffers from the same consistency issue as the M855, but to a higher degree.



Fackler was talking about the variations of yaw in flight causing performance differences in M193 in this paper on page 20:
https://thinlineweapons.com/IWBA/2001-Vol5No2.pdf


Figure 3 - These three wound profiles are variation
produced by the M 193 bullet fired from the M 16 A 1
rifle. The middle profile is the average one, seen in
about 70% of cases. The top and bottom profiles each
occur in about 1 5% of cases. The M 855 bullet fire
from the M16 A2 rifle produces similar profiles. Such
variations in wound profiles are seen with all full-metal
jacketed rifle bullets. This variation is most likely cause
by minute variations in the yaw angle as the bullet
strikes tissue or tissue simulant.



There isn't anything misleading about the Army or Facler talking about bullets that are dependent or not yaw dependent.
 
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