FMJ yaw and upset performance

[stanc]

Is there a link to the current version?

IIRC, I did read it online, but it was some years ago and I didn't consider it important enough to record the URL. Can only suggest google...

I wonder if any of our participants have enough background in interpretation of the law to do a non-binding pro bono review of the language and generate a summary of constraints?

As I recall, the Hague restrictions are quite specific, and those (i.e., the US JAG) who "interpret" it do so because they want it to mean something other than what it says.

And Gene, that's all I intend to say on the subject.

[LR1955]

I wonder if any of our participants have enough background in interpretation of the law to do a non-binding pro bono review of the language and generate a summary of constraints? That review and summary could go a long way toward minimizing confusion and blunting wishful thinking.

The result would add relevance to the discussions and greatly assist Tony on his side of the pond and some of us on this side when we make our case to decision makers.

Joe:

Not being a wise guy but why? The US has already determined that open tip match bullets are legal in combat. That happened circa 1991 if I recall correctly. Sure, one can argue the case either way but that argument was settled twenty years ago. For service ball, I doubt anyone is going to use an open tip match bullet due to cost.

Now, you better believe any potential enemy of ours will argue in the international courts to ensure we do not ever use a lethal bullet so what every design anyone tries to make according to international conventions will be argued in a court no matter what. It was done throughout the entire era of the various 5.56 bullets to include that hated 'Green Tip' M-855.

So, let me suggest that we get a bullet design that meets what ever requirements someone has in mind. Or maybe it would pay off more for someone here to specify the requirements for this bullet first and do it technically and specifically. Once the requirements are clear, then the design stuff can happen.

LR1955

[RangerRick]

LR1955

I believe we're interested in the same objective.

Absent a definitive summary of what is and is not allowed by the conventions, we fall prey to continuing speculation about "what if the bullet could..."

Tony's challenge is presenting a cartridge concept that will provide the desired effectiveness under the rules his nation is obliged to work under.

I see way too many references to US practice, including egregious extensions of that practice, in a thread motivated by UK and European needs.

So, the request for a more or less definitive summary is an attempt to keep the thread on track.

JASmith

Here is the Army Judge Advocate General's (JAG) deskbook on the Laws of war. It's a pdf document so you can search it. The x ray restriction is about fragmenting weapons, but a strict interpretation can include rifle bullets, as they can fragment. It has some stuff about the SMK.

http://www.fas.org/irp/doddir/army/deskbook.pdf


There are lots of treaties, conventions, laws, regulations, etc., etc. concerning this stuff with many amendments, so it gets complicated.

An Army buddy of mine once showed me some 300 Winchester magnum ammo that was "State Department Approved" for sniper work. They cost about $25 each. The requirement was to be able to penetrate the windshield of a 747 and still be accurate enough after penetration to take out a hijacker holding a gun on the pilot without hitting the pilot.

It was a bear to develop because the windshield is so thick and angled. Then the diplomats had to approve it.

[JASmith]

Joe:
...but why? The US has already determined that open tip match bullets are legal in combat...
LR1955

Gene,

I would concur with the 'but why?' sentiment if this were a thread dedicated solely to US interests.

The complication arises because the OP is working for a UK solution, and they have a much more restrictive interpretation. I have my personal thoughts about the wisdom of the interpretation but if we're to give Tony the support he needs we need to stay within the tighter rules.

I know you understand this, but others (including yours truly) occasionally forget!

Joe

[JASmith]

Here is the Army Judge Advocate General's (JAG) deskbook on the Laws of war...

Many thanks! I will use this...

I had run across the plastic restriction in another life, along with arcane things like beryllium.

The challenge for us in this thread, however, is that the question posed by the OP refers to the UK interpretation. I know enough to realize that he is stuck with that more strict interpretation.

[stanc]

The challenge for us in this thread, however, is that the question posed by the OP refers to the UK interpretation. I know enough to realize that he is stuck with that more strict interpretation.

It's been awhile since I read that section of the 1899 Hague dealing with small arms ammo, but I think I'm remembering correctly that it bans bullets which "expand or flatten easily" in flesh.

It's written in plain English. No interpretation needed...unless you want to make it seem as if expanding bullets like TSX and SOST are somehow lawful and don't violate that prohibition.

You're working too hard at this, Joe. It's simple, really. What Tony requires is a bullet that does not expand or fragment, but still rates high in lethality/incapacitation. Terminal yaw seems to be the only mechanism available to meet the specified need. No fragmenting bullets, no "barrier blind" expanding bullets, just good ol' non-deforming FMJ (like the US used to use before the mid-1950s).

[davidj]

Has anyone really thought how absurd this whole concept is. When you get hit it doesn't matter wtf the rules are. The politicians who make the unrealistic rules don't really care what the effect is on you. Believe me ...there is no humane way to kill a person. There is only a timely way to do it.

[stanc]

Has anyone really thought how absurd this whole concept is. When you get hit it doesn't matter wtf the rules are. The politicians who make the unrealistic rules don't really care what the effect is on you.

Yeah, in one sense the restriction on small arms ammo is absurd, especially considering all of the far more destructive weapons on the battlefield.

However, I think the guys who wrote the 1899 Hague agreement actually did care. The standard bullet type used back then (by everybody except the French, who had secretly developed a solid bronze, spitzer boattail projectile) was a round nose, flat base FMJ that penetrated straight through the human body, without yawing, deforming, expanding or fragmenting. If such bullets did not kill, they typically produced an easy-to-recover-from wound. That was in line with the idea that war (between nation-states) is essentially a game, and there is no reason to use bullets that inflict amputating injury, greviously maiming combatants who were wounded but not killed.

Of course, back then all the infantryman had to contend with were rifles and machine guns (and art'y). Today there are RPGs, Hellfire missiles, aircraft bombs, cluster munitions, and a host of other items extremely hazardous to the health.

[Tony Williams]

The exact wording of Declaration III of the 1899 Hague Convention is:

"The Contracting Parties agree to abstain from the use of bullets which expand or flatten easily in the human body, such as bullets with a hard envelope which does not entirely cover the core, or is pierced with incisions".

European lawyers interpret this to mean that the jacket must entirely enclose the nose of the bullet. The MK318 SOST definitely fails this test, and the M855A1 EPR technically does. As the EPR is designed to fragment easily, it also gets caught by the Geneva Conventions which prohibit the use of "weapons, projectiles and material and methods of war of a nature to cause superfluous injury or unnecessary suffering". This one is so vague it's a lawyers' delight.

Personally, I think that placing restrictions on bullet types like this is ridiculous - but my personal opinion does not matter. This is the situation we are faced with on this side of the Pond, and which caused the UK to introduce a thicker jacket for their 5.56mm because the original fragmented too easily.

So yes, yaw performance is the key to terminal effectiveness, and that is difficult to combine with other requirements. This makes the design of the bullet essential to get right - it's the first priority, and may even determine what calibre the bullet comes in. Everything else follows from that.

Incidentally, some of the more radical types in the International Red Cross (who monitor these things) would like to see bullets which yaw banned as well. In which case, we'd be back to round-nose bullets which rely on calibre to do the job, and the choice would be between a .458 SOCOM and a .50 Beowulf!

[JASmith]

Tony and Stan,

Thanks -- that should have cleared the air!

Cheers!
Joe

[stanc]

So yes, yaw performance is the key to terminal effectiveness, and that is difficult to combine with other requirements. This makes the design of the bullet essential to get right - it's the first priority, and may even determine what calibre the bullet comes in. Everything else follows from that.

How quickly do you want the bullet to yaw? The relatively stubby 6.8mm 115gr SMK has a neck length of a little more than an inch, and the more streamlined 6.5mm 123gr SMK is about 2.5 inches. While both of these are "open tip" designs, and therefore not themselves suitable for your purpose, I think they demonstrate what should be achieveable with similar FMJs.

[stanc]

Tony, if it'll help, the following was originally posted by Bill A back in late 2007.
----------------------------
The attached photograph shows the following projectiles (left to right)

i) 120 grain Berger (Bc=0.492). Thin hard jacket that will fragment easily.
ii)100 grain Lapua Scenar (Bc=0.444). This is the shortest jacket in this projectile class. Note that the nose closure is greater than any of the SMK projectiles and that the lead core is pressed flat on the front. Equally note the jacket weight. The Scenars all have heavy ductile jackets which restrict fragmentation but do deform and tumble.
iii)108 grain Lapua Scenar (Bc=0.478). Shares a common jacket with the 123 Scenar.
iv)123 grain Scenar (Bc=0.547) As above note tip closure, jacket weight and core finish.
v)107 grain SMK (Bc=0.407) The jacket is slightly thinner and is less ductile but the tip closure on this projectile are very close to the equivelent Lapua projectile. Note the formation of the lead core at the front into a standing short cylinder.
vi)120 grain SMK (Bc=0.420) The jacket on this projectile is noticably thinner than the equivelent Scenar and even the Berger. This projectile has the most open tip of the 6.5mm projectiles.
vii)123 grain SMK (Bc=0.510) The construction bar core length is practically identical to the 107 SMK. This round does fragment well in gelatine and the tip is well closed. The core extends further into the jacket nose than the 123 Lapua due to a shorter bullet length and the formation of the short cyclinder on the core front seen on all the SMK.
viii) 115 grain 6.8 SMK (Bc=?) This example is pre canelure but shows a heavy thickening as the nose is formed. The lead cylinder on the core front is still present but the stubby ogive has mainly deformed its presence. The nose is well closed but the airspace at the front of the jacket is present.
ix)115 grain Hornady (Bc=0.320) Current production example. Note the jacket weight and the open tip. There is little airspace within this the jacket nose.
x) 115 grain Hornady (Bc=?) Older production example. The jacket is very noticably thinner than the current bullet and the lead core itself carries a cavity, although this is closed slightly by the action of forming the projectile nose.
----------------------------
Unfortunately, I don't recall if Scenar gel tests were ever posted. If such can be had, it would give a better representation of what non-fragmenting 6.5mm FMJ wound trauma would be like.

Stan

[Tony Williams]

Thanks for that, Stan. The 6.5mm Scenar performance looks very good to me - I was thinking in terms of yaw starting after no more than 2 inches and turnover being complete within 12 inches.

If the bullet doesn't deform then replicting that performance with an FMJ shouldn't be too difficult. Doing so in a production ball bullet without losing too much of the ballistic coefficient may be more of a challenge.

And then there's the big unknown - the consequences of using copper+steel-cored "green" bullets.

[JASmith]

As we move forward, we need to think about experimental standards to assess whether a bullet will "...expand or flatten easily in the human body..." This would give us a more objective standard.

The language above uses the term "easily" as a modifier. Further the exposed lead and slits were specifically cited.

So, has the UK already adopted a standard for testing to determine if a particular bullet deforms or flattens easily?

If not, I would suggest the classic gelatin test as a standard. For example, the bullet not deform beyond a specified amount on penetration a gelatin block placed 20 meters from the muzzle for a standard velocity cartridge.

Further, I would argue against including barriers or bone simulators in the gelatin. Any barrier is beyond the scope of the agreement. A rigid projectile impacting bone will generate secondary fragments (chunks of bone) so the additional requirement could be argued as excessive.

[stanc]

I am interesting in promoting the idea of a long-range intermediate military cartridge capable of replacing both 5.56mm and 7.62mm NATO rounds.

The problem is, I have read in a British report that in a gel test by Alexander Arms of an FMJ bullet fired from a Grendel case, it did not start to yaw until after penetrating several inches, which is not good enough.

So I really have a two-part question here:

1. Is it possible to design a low-drag 6.5mm FMJ bullet of around 120-125 grains which exhibits rapid and reliable yaw and upset on impact?

2. Is it possible to achieve the same performance using a lead-free bullet, since that seems to be a growing military requirement?

Tony, I should've asked this earlier. I know that on your website you show some photoshopped pics of possible 6.5, 6.8 and 7mm cartridges. Does item 1 above mean that you've settled on 6.5mm? Are you planning to create one or more "wildcat" cartridges to do load development and terminal effectiveness tests? If so, do you intend to have custom bullets made for you?

FWIW, in addition to the 120gr 6.5mm FMJ, Norma also shows a 130gr .270 FMJ and 150gr 7mm FMJ.
http://www.norma.cc/content.asp?Typ=28&L...Components

[stanc]

Tony, I was just rereading your "Next Generation" article ( http://www.quarry.nildram.co.uk/The%20Ne...ration.htm ) and was intrigued by the following comment:

Ironically, the EM-2's 7x43 cartridge might actually prove to be a good basis for such tests since it has the same case diameter as the 7.62 NATO, so rebarrelling existing 7.62 weapons should in principle be easy. Even the same belt links can be used.

At first, I thought that was a great idea, as one might even be able (albeit at some expense) to buy up enough 7x43 rounds for preliminary testing. Unfortunately, as I looked at the photo of the 7x43 and 7.62x51 side-by-side, it occurred to me that the old .280 British has the same problem in using M13 links as does 6.5 Grendel with the M27 link design, only more so.

I see no way that 7.62x51 links can be used to feed 7x43, because the foward link loop would extend beyond the 7x43 shoulder almost up to the neck. See attached.

[Tony Williams]

Tony, I was just rereading your "Next Generation" article ( http://www.quarry.nildram.co.uk/The%20Ne...ration.htm ) and was intrigued by the following comment:



At first, I thought that was a great idea, as one might even be able (albeit at some expense) to buy up enough 7x43 rounds for preliminary testing. Unfortunately, as I looked at the photo of the 7x43 and 7.62x51 side-by-side, it occurred to me that the old .280 British has the same problem in using M13 links as does 6.5 Grendel with the M27 link design, only more so.

I see no way that 7.62x51 links can be used to feed 7x43, because the foward link loop would extend beyond the 7x43 shoulder almost up to the neck. See attached.

Yes, it does - I have some 7x43 dummies in 7.62mm links, made by a small ammo firm in the UK. They tried out a short length of belt by manually cycling it through a GPMG, and reported that the belt and rounds fed just fine (although the rounds obviously then disappeared up the too-long chamber!).

[Tony Williams]

Tony, I should've asked this earlier. I know that on your website you show some photoshopped pics of possible 6.5, 6.8 and 7mm cartridges. Does item 1 above mean that you've settled on 6.5mm? Are you planning to create one or more "wildcat" cartridges to do load development and terminal effectiveness tests? If so, do you intend to have custom bullets made for you?

I have always had a preference for 6.5mm since I think this provides more advantages over 7.62mm than 6.8mm or 7mm would, in terms of weight, trajectory and recoil. Provided of course, that the performance requirements can be met.

However, someone who knows more about bullet design than I do has expressed a view that there could be problems in designing a lead-free 6.5mm bullet of 120-125 grains with the required ballistic coefficient (.500+), since it would be very long, maybe creating stabilisation issues. It might therefore be necessary to drop the BC somewhat, in which case a larger calibre might better suited: it would keep the same overall length but with a lower LD ratio. So I'm keeping my options open.

There are no firm plans yet over developing a round, but confidential discussions are ongoing...

[JASmith]

...someone ... has expressed a view that there could be problems in designing a lead-free 6.5mm bullet of 120-125 grains with the required ballistic coefficient (.500+), since it would be very long, maybe creating stabilisation issues. It might therefore be necessary to drop the BC somewhat, in which case a larger calibre might better suited: it would keep the same overall length but with a lower LD ratio...

Tony,

Getting a bullet to tumble immediately on impacting a soft medium means that you will be working with one that is marginally stable in flight. I suspect you will have stabilisaton issues regardless of caliber.

To the best of my knowledge, the factors of concern for stability are the overall length, bullet weight (or density), velocity, and twist rate. Has anyone looked at the twist rate needed to stabilize a 123 gr solid copper bullet in 6.6mm? There's at least one on-line implementation of the Greenhill formula.

The other, perhaps more challenging, issue is the space taken up bu the long bullet. This favors the smaller bullet.

We can arbitrarily add length to account for voids, trace materials, etc. if it's deemed necessary for the yaw performance and compute the twist needed.

Barnes bullets offers a solid (no-lead) 110 gr bullet with an interesting ballistic coefficient:

.264" 110-gr Banded Spitzer BT SD=.225 BC=.452

They make no special twist rate call-out for this offering. One would think that this bullet is in the right ballpark.

Here's a couple of sources of very long solid bullets in 6.5mm. They might be able to give recommended twist rates based on actual tests:

http://www.barnesbullets.com/products/ri...ed-solids/
http://www.gsgroup.co.za/sp.html and,
http://www.thegunroomuk.com
http://www.barnesbullets.com/products/ri...sx-bullet/

[Tony Williams]

Thanks for the links, Joe. The next question is obviously - to what degree can these BCs be replicated in a mass-production military ball round?