Part II of "Requirements for replacements of currently issued 5.56 M-855 and 7.62 M-8

[JASmith]

Our discussions in Requirements for Replacement of Currently Issued 5.56 M-855 and 7.62 M-80 (http://www.65grendel.com/forum/showthread.php?405-Requirements-for-Replacement-of-Currently-Issued-5.56-M-855-and-7.62-M-80./page3) have raised a number of fascinating issues. The original post laid down a challenge to flesh out the need and, possibly, draft an informal requirements statement. To that effect, Tony Williams posted a first cut in #6 (http://www.65grendel.com/forum/showthread.php?405-Requirements-for-Replacement-of-Currently-Issued-5.56-M-855-and-7.62-M-80.&p=3111&viewfull=1#post3111) on 05-8-2011. That was followed by an initial expansion by LR1955 in #25 (http://www.65grendel.com/forum/showthread.php?405-Requirements-for-Replacement-of-Currently-Issued-5.56-M-855-and-7.62-M-80.&p=3193&viewfull=1#post3193). LLRPF52 posted in #65 (http://www.65grendel.com/forum/showthread.php?405-Requirements-for-Replacement-of-Currently-Issued-5.56-M-855-and-7.62-M-80.&p=3481&viewfull=1#post3481) what appears to be an important clarification in that the focus on weight reduction to facilitate movement by soldiers on foot suggests that we are primarily focusing on the needs of dismounted light infantry.

The vision is a single cartridge to be used in the span of weapons including carbines (e. g., M4) rifles (e. g., the DMR role), light machine guns, and general purpose machine guns used by dismounted light infantry.

The discussions in the referenced thread are continuing to explore related topics but, with the number of posts approaching 130(!), one's ability to track back to references is becoming stressed. Hence this restart with, hopefully, a stronger emphasis on moving smartly to a complete notional requirement statement.

The plan is to work through the list presented by Tony and amended by LR1955, consolidating points as needed, and produce statements that cartridge options can be analytically tested and, where appropriately evaluated by trials. The next two posts are updated drafts of the notional requirements for external ballistics and for barrier penetration.

Let's cuss and discuss, tweak them, and then move on to the next item in the draft list!

[JASmith]

Threshold:


Equal or better the vertex and wind drift of the 7.62X51 M80 at 300 and 1000 metres when using a 20-inch barrel.

Objective:


Equal or better the vertex and wind drift of the 20-inch barrel 7.62X51 M80 at 300 and 1000 metres when using a 14-inch barrel.
Rationale: The trajectory of the 7.62 from standard-length barrels is a known and accepted performance level. Any new ammunition type will need to perform at least as well in the emerging new and shorter standard barrel lengths. Meeting or beating the 7.62 trajectory at either 300 or 1000 meters assures that the trajectory performance will be better than that of the 5.56 M855

[JASmith]

Threshold: Steel plate defeat

Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can perforate a 3.5 mm (10 gauge) steel plate when using an open tip match bullet (E. g., Sierra Match King, Berger Match, etc.).
Rationale: This threshold requirement establishes a relationship between bullet velocity, mass and diameter when standard bullets are used. The thickness specified is approximately the total thickness obtained when the three plates of the target defined in STANAG 4498 (NATO Medium Truck). The bullet selection is restricted to permit a near-standard comparison across calibers and to establish a minimum cartridge size for barrel length. The performance of the open tip match bullet on this target is presumed to match that of classic lead-filled full-metal jacketed bullets. The match bullets are specified to provide a wide variety of bullet weights while maintaining a standard bullet design class.

Objective 1: Spaced Steel plate defeat

Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can perforate the STANAG 4498 target at when the bullet impacts at 45 degrees from normal when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.
Rationale: Meeting the threshold with the open tip match bullet as specified is the first step in a multistep design. Perforating the spaced plate at an angle is a significant increase in challenge. This added challenge may be met by upgrading the bullet design from open tip match to one that coincidentally more nearly satisfies the intent spelled out in the Hague and Geneva conventions relating to military small arms

Objective 2: Windshield defeat

Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can defeat the target spelled out in "FBI Test 6" when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.
Rationale: This objective completes the vehicular defeat requirements spelled out above. As in Objective 1, this added challenge may be met by upgrading the bullet design from open tip match to one that coincidentally more nearly satisfies the intent spelled out in the Hague and Geneva conventions relating to military small arms

Objective 3: SAPI Defeat

Defeat the NIJ Level III target with one fair hit when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.
Rationale: Level III armor is designed to absorb as many as six fair hits of the M80 bullet at 2780 ft/sec prior to failure.

References:
A discussion of SAPI plates is here - http://en.wikipedia.org/wiki/Small_Arms_Protective_Insert
NIJ Standard-0101.05 is defined here: www.ncjrs.gov/pdffiles1/nij/223054.pdf and specifies protection level

FBI Test 6 spelled out here: http://greent.com/40Page/general/fbitest.htm

[stanc]

Threshold: Steel plate defeat

Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can perforate a 3.5 mm (10 gauge) steel plate when using an open tip match bullet (E. g., Sierra Match King, Berger Match, etc.).
Rationale: This threshold requirement establishes a relationship between bullet velocity, mass and diameter when standard bullets are used. The thickness specified is approximately the total thickness obtained when the three plates of the target defined in STANAG 4498 (NATO Medium Truck). The bullet selection is restricted to permit a near-standard comparison across calibers and to establish a minimum cartridge size for barrel length. The performance of the open tip match bullet on this target is presumed to match that of classic lead-filled full-metal jacketed bullets.
I dunno if it's a good idea to make that presumption. The more fragile tip construction of HPBT match bullets may well result in less penetration compared to FMJ, especially the (steel-tip) M855 round. However, if one could establish that penetration of, for example, 150gr .308 MatchKing is the same as 147gr M80 FMJ... If you're not going to compare candidate cartridges w/FMJ bullets to M80 and M855, might it be better to compare MatchKings (or Bergers, etc) in 5.56 and 7.62 to the new caliber?

FWIW, once upon a time I shot at a 3.5mm thick steel plate (of unknown hardness) at a distance of ~400 yards, using 7.62 M80 and 5.56 M193. The 7.62 punched through the plate; 5.56 merely dented it. Anyway, the point is that whomever might conduct such a test will need significantly longer than a 400-yd range to do it.

Concur with your objective requirements.

[LRRPF52]

Gents,

It seems important to recognize the different types of duty positions that have been brought up in these threads. Here are some basic categories of jobs in the military land forces components:

A. Dismounted Light Infantry/Airborne/Airmobile Combat Arms Soldiers & Attachments who will seek to close with and destroy the enemy

This includes dozens of duty positions that have a role that is not what a rifleman's is. The rifleman's job is roughly: to provide direct small arms fire on enemy soldiers and equipment while closing with and destroying the enemy using fire & maneuver or direct close combat. These attached or organic combat support personnel will be right next to or somewhere in the order of movement within an Infantry Platoon, but will have duties that focus their attention on tasks other than using a carbine to individually shoot enemy soldiers. This includes combat medics, assistant gunners, radio operators, key leaders (although they usually carry what riflemen carry), anti-armor missile gunners, forward observers for managing indirect and Close Air Support assets, etc.

B. Motorized/Mechanized Infantry who dismount from vehicles and work with vehicles as their fire support elements

C. Combat Service Support Personnel (now called Sustainment): Those who would be served well with a PDW, as they are not directly seeking to locate, fix, close with, and destroy the enemy, but have crew-served weapons on their vehicles for convoy security, and traditional rifles currently for personal defense.

I think everyone would agree that the M16A2 is not a good fit for all these personnel, and many units have replaced it with the M4. I could argue in favor of an even shorter barrel for the M4 for the majority of dismounts in a Light Infantry unit who are not riflemen, and most of them would welcome that from a strictly carry/weight/profile perspective.

The argument could be made without much protest that whatever standard service weapon is good for riflemen in Light Infantry is good for riflemen in Mech Infantry, since they basically function like Light Infantry for short durations once they exit the vehicles, and shorter weapons facilitate better interoperability from vehicles as well.

The requirements for individual weapons for support personnel can be argued in both ways, since reliance on the crew-served weapons for distance is negated when they are forced from their vehicles. The M4 is a good balance currently of profile/weight and range, since most support personnel couldn't exploit the effective range of even the M4, but they could put up good resistance at maybe 100-200m with individual weapons on a good day. We could get carried away from what our primary focus should be though, and I submit that focus should be with the ground-pounders first and foremost.

Then we have to identify the different types of weapons that dismounted Infantry soldiers carry, and how they work together to achieve the maximized casualty results on enemy forces, as well as their ability to engage and defeat light-skinned vehicles.

While there are tens of thousands of soldiers currently deployed to Afghanistan, we also have to remember that they are fighting irregulars who use tactics that don't involve the logistics, vehicles, and combined arms teams of modern armies. We should be careful about forming any requirements for weapons that tailor to that situation more than others, but still keep in mind that small arms are probably not so negatively influenced by either the unconventional and conventional battlefield requirements.

Looking at the various duty positions in a dismounted Light Infantry unit, I have to come to the conclusion that there will in fact be several types of ammunition issued, and at least 2 chamberings for shoulder-fired weapons, to include machineguns. It also makes sense that some of the weapon profile requirements for a support MOS could overlap with a Combat Medic, a Forward Observer, a Radio Operator, and even some key leaders like 1st Sergeants, Company Commanders, etc. In the Infantry, I could easily be swayed with an argument to replace the sidearm with a modern PDW with a more effective cartridge as seen with the 6.5x25 CBJ.

That would create a 3-caliber system for the Infantry Platoon replacing 9mm simultaneously, leaving the other two chamberings for riflemen and machinegunners. That would be the leanest and most practical move going forward, and we have seen this approach developing in China and Russia, with the small bottle-necked PDW cartridges at least.

LRRPF52

[LRRPF52]

FWIW, once upon a time I shot at a 3.5mm thick steel plate (of unknown hardness) at a distance of ~400 yards, using 7.62 M80 and 5.56 M193. The 7.62 punched through the plate; 5.56 merely dented it. Anyway, the point is that whomever might conduct such a test will need significantly longer than a 400-yd range to do it.

The M855 seems to outperform the M80 on steel plate penetration, but I'm not sure what distance they reach equilibrium. As far as range goes, the only limitations I have in both areas where I would propose to conduct these types of tests is the rifle/ammunition/optics. I shoot in the high desert in Utah, as well as on artillery test ranges near the Arctic Circle in Northern Europe, so finding the right settings, to include extremes on both ends of the weather conditions in both locations, is not an issue. Utah provides a hot/dry, cold wet environment, while the northern hinterland location provides an extreme cold/wet, extreme hot/wet environment. Both have plenty of wind effects too.

LRRPF52

[JASmith]

...If you're not going to compare candidate cartridges w/FMJ bullets to M80 and M855, might it be better to compare MatchKings (or Bergers, etc) in 5.56 and 7.62 to the new caliber? ...
Good point -- the threshold is really trying to establish the weight and velocity needed for the caliber. Further, the M855 design means that using it to compare for this exercise defeats the principle of "like to like" bullet construction.

So, I've changed the master copy to read:

Threshold: Steel plate defeat

Perforate a 3.5 mm (10 gauge) steel plate at a lower velocity than with a 150 gr .308 bullet when using an open tip match bullet in both calibers.
I also updated the rationale to indicate "The comparison can be made by establishing the V50 velocity for each caliber and bullet being considered."

Note that the range is deliberately left unstated, which opens the option for testing at ranges of a few tens of meters using reduced loads.

[JASmith]

From all appearances, the success of Tony's vision will largely hinge on increasing the number of rounds of small arms ammunition carried by the foot soldier while maintaining the per round effectiveness of the 7.62X51 NATO M80 ammunition type. The weapons include the carbine, the rifle to include designated marksman applications, light machine gun, and general purpose machine gun.

The drive is to improve the capabilities of dismounted versus motorized infantry. Ammunition weight, while important, is less of a constraint for weapons used by infantry when firing from vehicles.

BTW -- If the Rumsfeld acquisition doctrine still holds, we will need to describe the motivation in terms of filling a capability gap. The logic is that we can't afford to merely improve a component or system. We must first identify a capability that we don't have, need, and can't find a suitable work around.

In addition, I have the strong feeling that we are overlooking a significant strengthening of the motivation for what we're doing by not referencing any operational analyses that suggest a need for the ability to marry single round effectiveness of the 7.62X51 M80 round with the weight of 5.56 NATO ammunition.

I have also included the two requirements we've already reviewed.

PARTIAL DRAFT REQUIREMENTS:

Principal Requirement: Weight Reduction

Threshold:


Increase the number of rounds carried in magazines and belts by 25% for the same weight while using standard materials, e, g, brass and steel, as current 7.62X51 NATO ammunition while retaining at least the individual round effectiveness of the 7.62X51 NATO M80 round.

Objective:


Increase the number of rounds carried in magazines and belts by 50% for the same weight while using standard materials, e, g, brass and steel, as current 7.62X51 NATO ammunition while retaining at least the individual round effectiveness of the 7.62X51 NATO M80 round.

Rationale: Many user reports indicate a strong preference for the trajectory, lethality and barrier penetration of the 7.62X51 NATO M80 ammunition type, but suggest that the weight penalty has a significant impact on movement of dismounted infantry. The requirement for increased ammunition carry therefore includes the caveat that individual round effectiveness be maintained. Factors by which the effectiveness will be judged are spelled out in the following supplemental requirements.

Requirement 1: External Ballistics

Threshold:


Equal or better the vertex and wind drift of the 7.62X51 M80 at 300 and 1000 metres when using a 20-inch barrel.

Objective:


Equal or better the vertex and wind drift of the 20-inch barrel 7.62X51 M80 at 300 and 1000 metres when using a 14-inch barrel.
Rationale:
The trajectory of the 7.62 from standard-length barrels is a known and accepted performance level. Any new ammunition type will need to perform at least as well in the emerging new and shorter standard barrel lengths. Meeting or beating the 7.62 trajectory at either 300 or 1000 meters assures that the trajectory performance will be better than that of the 5.56 M855[/QUOTE]

Requirement 2: Barrier Penetration

Threshold: Steel plate defeat

Perforate a 3.5 mm (10 gauge) steel plate at a lower velocity than with a 150 gr .308 bullet when using an open tip match bullet in both calibers.
Rationale: This threshold requirement establishes a relationship between bullet velocity, mass and diameter when standard bullets are used. The thickness specified is approximately the total thickness obtained when the three plates of the target defined in STANAG 4498 (NATO Medium Truck). The bullet selection is restricted to permit a near-standard comparison across calibers and to establish a minimum cartridge size for barrel length. The performance of the open tip match bullet on this target is presumed to match that of classic lead-filled full-metal jacketed bullets. The match bullets are specified to provide a wide variety of bullet weights while maintaining a standard bullet design class.

The comparison can be made by establishing the V50 velocity for each caliber and bullet being considered. V50 is the velocity at which approximately half of the bullets perforate and the other half don't.

Objective 1: Spaced Steel plate defeat

Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can perforate the STANAG 4498 target at when the bullet impacts at 45 degrees from normal when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.
Rationale: Meeting the threshold with the open tip match bullet as specified is the first step in a multistep design. Perforating the spaced plate at an angle is a significant increase in challenge. This added challenge may be met by upgrading the bullet design from open tip match to one that coincidentally more nearly satisfies the intent spelled out in the Hague and Geneva conventions relating to military small arms

Objective 2: Windshield defeat

Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can defeat the target spelled out in "FBI Test 6" when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.
Rationale: This objective completes the vehicular defeat requirements spelled out above. As in Objective 1, this added challenge may be met by upgrading the bullet design from open tip match to one that coincidentally more nearly satisfies the intent spelled out in the Hague and Geneva conventions relating to military small arms

Objective 3: SAPI Defeat

Defeat the NIJ Level III target with one fair hit when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.
Rationale: Level III armor is designed to absorb as many as six fair hits of the M80 bullet at 2780 ft/sec prior to failure.

References:
A discussion of SAPI plates is here - http://en.wikipedia.org/wiki/Small_Arms_Protective_Insert
NIJ Standard-0101.05 is defined here: www.ncjrs.gov/pdffiles1/nij/223054.pdf and specifies protection level

FBI Test 6 spelled out here: http://greent.com/40Page/general/fbitest.htm[/QUOTE]

[stanc]

Requirement 2: Barrier Penetration

Threshold: Steel plate defeat

Perforate a 3.5 mm (10 gauge) steel plate at a lower velocity than with a 150 gr .308 bullet when using an open tip match bullet in both calibers.
Rationale: This threshold requirement establishes a relationship between bullet velocity, mass and diameter when standard bullets are used. The thickness specified is approximately the total thickness obtained when the three plates of the target defined in STANAG 4498 (NATO Medium Truck).

Objective 1: Spaced Steel plate defeat

Equal or exceed the range at which the 7.62mm M80 round or the 5.56 M855 round from a 20" barrel can perforate the STANAG 4498 target at when the bullet impacts at 45 degrees from normal when using any bullet design with the mass and velocity established by meeting threshold with the standard bullet.
Joe, why a single (relatively thick) steel plate for threshold, but spaced, thin steel sheets for objective? Shouldn't both requirements use the same 4498 target?

BTW, this reminds me of something I learned in past testing. Penetration of spaced (thin) steel is different than for a thick steel plate. Example: 9mm Ball punched through eight (8) thin steel sheets, but barely dented a 3.5mm thick plate.

[HANKA]

As always very good stuff, guys.

The practical test I would like to see is an apples-to-apples comparison of optimized loadings (not necessarily peak velocity, but loadings pressure-approved in all temperature extremes) in identical barrel lengths using similar projectiles on identical target test mediums.

OPEN TIP MATCH BULLETS

5.56N = 77gr Sierra MatchKing (Mk262)

6.5G = 123gr SMK

7.62N = 175gr SMK (M118LR)

FULL-METAL JACKET

5.56N = 62gr M855A1 (Liberty Ammunition's copper body, steel tip T3 bullet design)

6.5G = 110gr T3

7.62N = 147gr T3

I realize it's kind of jumping the gun to just ad hoc test something without thinking through what it is we really want, but with this I'd like to establish a baseline to have some data on where we're at with state-of-the-art, but off-the-shelf technology.

John

P.S. It also occurs to me that Barnes has an extensive TTSX line of bullets that should include the three calibers mentioned above, for an apples-to-apples comparison of the relative performance of those projectiles.

[JASmith]

Joe, why a single (relatively thick) steel plate for threshold, but spaced, thin steel sheets for objective? Shouldn't both requirements use the same 4498 target?

BTW, this reminds me of something I learned in past testing. Penetration of spaced (thin) steel is different than for a thick steel plate. Example: 9mm Ball punched through eight (8) thin steel sheets, but barely dented a 3.5mm thick plate.
The full STANAG target at 45 degrees is significantly more challenging than the single 3.5mm (10 gauge) steel plate face-on. The reason is the angle of impact initiates rotation of the bullet (tipping) and the gap gives time for the bullet to rotate. The second barrier makes it more acute, and the third being a little thicker might even deflect a bullet with marginal characteristics.

Recall that the purpose of the threshold is to force a minimum mass and velocity combination for the caliber. We can get by with the OTM bullets on the single plate, because they behave better on this kind of target than on the spaced plate.

Hence the objective targets force improved bullet design on barrier penetration with a rational starting point for bullet weight.

[stanc]

The practical test I would like to see is an apples-to-apples comparison of optimized loadings (not necessarily peak velocity, but loadings pressure-approved in all temperature extremes) in identical barrel lengths using similar projectiles on identical target test mediums.

5.56N = 77gr Sierra MatchKing (Mk262)
6.5G = 123gr SMK
7.62N = 175gr SMK (M118LR)

5.56N = 62gr T3
6.5G = 110gr T3
7.62N = 147gr T3

I realize it's kind of jumping the gun to just ad hoc test something without thinking through what it is we really want...
John, I don't consider it at all jumping the gun. IMO, there is enough published info on the testing done by the US Army (and the FBI), to do more than ad hoc tests.

...but with this I'd like to establish a baseline to have some data on where we're at with state-of-the-art, but off-the-shelf technology.
AA has 6.5mm 110gr T3 bullets? Excellent! :cool:

And I wholeheartedly agree with the desire for test data. IIRC, a "board curmudgeon" on the old forum had been pleading for such tests for several years... ;)

P.S. It also occurs to me that Barnes has an extensive TTSX line of bullets that should include the three calibers mentioned above, for an apples-to-apples comparison of the relative performance of those projectiles.
Not sure if TTSX would yield much useful info beyond relative performance of that particular (non-military) type bullet. FWIW, relative performance could also be tested with a number of other hunting bullets.

However, the SMK and T3 I fully agree with, since those types are used by the military. Also, 5.56mm 70gr and 6.5mm 120gr TSX in 10.5" barrel CQBR, used by SOCOM.

Additionally, since Tony thinks the UK and Europe would require FMJ, I'd add the Norma 6.5mm 120gr FMJ vs 7.62mm M80 FMJ, 5.56mm lead-core 62gr FMJ and 5.56mm M855. I'd much prefer the Wolf 6.5mm 110gr FMJ over the Norma bullet, but you know how that story goes... :(

P.S. Regarding the UK/European requirement for a non-deforming, non-fragmenting FMJ, the Barnes 6.5mm 110gr solid might be a viable surrogate for test purposes.

[stanc]

Joe, while going through my files today, I came across this bit:

"[The] NATO standard, mild steel test plate...defines the penetration performance required of NATO rifle ammunition. It simulates the penetration deemed necessary to produce a lethal wound against enemy personnel protected by steel helmets and body armor, and to penetrate reasonable cover. The plate is 3.5mm (.138") thick, of AISI 1010 or 1020 equivalent mild steel of Rockwell hardness B55-70. Acceptance standards for 5.56mm NATO ammunition require all rounds (except tracers) to perforate this plate at 570 meters (623 yds.) under standard atmospheric conditions."

C. E. Harris, "How Does NATO's New 5.56mm Round Measure Up?", American Rifleman, May 1982, pp. 77-78.

Does this help?

[stanc]

The practical test I would like to see is an apples-to-apples comparison of optimized loadings in identical barrel lengths using similar projectiles on identical target test mediums.

5.56N = 77gr SMK (Mk262)
6.5G = 123gr SMK
7.62N = 175gr SMK (M118LR)

5.56N = 62gr T3 (M855A1)
6.5G = 110gr T3
7.62N = 147gr T3 (M80A1-A)

I'd like to establish a baseline to have some data on where we're at with state-of-the-art, but off-the-shelf technology.
John, I'd like very much to see such baseline data. If nothing else, it would tell us if the intermediate caliber concept is worth pursuing any further.

And if the T3 loads are not actually available for testing, I'd substitute the following comparison:

FMJ (lead core)

5.56N = 62gr (Winchester USA223R3?)
6.5G = 120gr (Norma)
7.62N = 147gr (M80)

So, will we see this baseline testing done? If so, when?

[JASmith]

Guys -- we aren't ready to test.

Points to consider:

What cartridge is the "optimized loading" in?
How is the cartridge selected or defined?
The suggested weights appear to give an unfair advantage to 6.5 mm because that bullet has the highest sectional density in the list.
The targets/test media are not defined.
Some communication, most likely informal, needs to happen with develop, procurement, or political entity to assure the test means something to a decisionmaker.

Regarding the unfair advantage mentioned above. The 'optimized loadings' might mean consistent muzzle velocity, consistent impact velocity, or the best one could do with his favorite cartridge. The least desirable choice is somebody's favorite cartridge in a caliber.

What I do know is that a poorly designed test will do more harm than good because it can:

appear to contradict one's expectations -- Reversing the results of an apparent failure in a test are extraordinarily difficult.
appear to incorrectly favor your expectation -- creating a credibility issue


Last point -- we are looking at a cartridge that, round for round, is about the same or a tad better in some areas in the 7.62X51 but can function in the AR-15 class of rifles. I maintain that we already know that's doable. We lack the story that puts the test in context.

[stanc]

Guys -- we aren't ready to test.
Joe, I respectfully disagree. I say that testing is long overdue.

What cartridge is the "optimized loading" in?
6.5 Grendel (according to my reading of John's post).

How is the cartridge selected or defined?
6.5 Grendel (as denoted by John).

The suggested weights appear to give an unfair advantage to 6.5 mm because that bullet has the highest sectional density in the list.
5.56x45 and 7.62x51 are the current NATO standard cartridges, against which proposed replacements will necessarily have to be compared. If the 6.5mm bullets have higher sectional densities, that's not an "unfair" advantage, it's just a characteristic.

What would be unfair is placing an arbitrary limitation on sectional density.

The targets/test media are not defined.
That's easy enough to do. It just wasn't necessary to cover specific tests in John's post.

Some communication, most likely informal, needs to happen with develop, procurement, or political entity to assure the test means something to a decisionmaker.
I consider that premature.

First, there needs to be adequate testing done (w/currently available bullets) to determine if 6.5 Grendel actually is a viable replacement for 5.56 and/or 7.62 NATO.

If those initial tests show that 6.5 Grendel is not superior (or not sufficiently so to be worthwhile), then development of better bullets should be pursued before contacting any government or military entities.

Regarding the unfair advantage mentioned above. The 'optimized loadings' might mean consistent muzzle velocity, consistent impact velocity, or the best one could do with his favorite cartridge.
For the sake of brevity, I omitted John's judgment on what constitutes an optimized loading: "...not necessarily peak velocity, but loadings pressure-approved in all temperature extremes..." http://www.65grendel.com/forum/showthread.php?499-Part-II-of-quot-Requirements-for-replacements-of-currently-issued-5.56-M-855-and-7.62-M-8&p=4146&viewfull=1#post4146

The least desirable choice is somebody's favorite cartridge in a caliber.
Now, that ain't necessarily so. It could prove to be the most desirable.

What I do know is that a poorly designed test will do more harm than good...
So use the same tests that the military employs.

Last point -- we are looking at a cartridge that, round for round, is about the same or a tad better in some areas in the 7.62X51 but can function in the AR-15 class of rifles. I maintain that we already know that's doable.
Yes, we know that 6.5 Grendel works in the AR-15, and in theory, equals or exceeds some aspects of 7.62 NATO performance.

What we lack is a reality check, hard data to confirm (or refute) the theory.

[JASmith]

...What we lack is a reality check, hard data to confirm (or refute) the theory.
Frankly, I would welcome some neat pictures of holey metal and splashed gelatin, but I cannot in all honesty advocate those tests until we're pretty sure the rest of the story holds water. I guess that part of my reticence is that folks have been popping various targets for longer than we've had gunpowder.

At this point we have what is best described as an idea based on some excellent design and development work by Alexander Arms. Many of us have followed your lead in recognizing the Grendel as a very attractive cartridge with the potential to replace both the 7.62X51 and the 5.56 NATO in the weapons used by dismounted infantry.

Tests showing holes in things are about a dime a dozen, unless they are tied to a story. LR1955 has indicated more than his personal views in the questions and challenges he gave us when he started Part I of this thread. He correctly points out that probability of hit is a major factor. He also tells us that flatter trajectories inside of 500 meters are an important factor in improving probability of hit by the normal infantryman. These won't be resolved by the suggested tests.

We're working toward formalizing the discussion in a format similar to that normally employed in articulating requirements for a capability. One of the advantages is that working through the document helps us be sure we've captured the less obvious, but still critical, issues that go into making a particular concept useful in the acquisition sense. Even more important, we get to identify the things that are most critical so that those who have the resources and are willing to expend them will have better confidence that their tests and analyses have meaning.

The whole point of this thread is to develop that story by:


describing the needs and goals,
articulating the needs and goals in a way that allows analytic testing of alternative solutions, and
defining physical tests to determine which, if any, of the alternative solutions meet the threshold needs.


Once we've got the major details nailed down, I will become part of the choir singing for tests...

[JASmith]

Here's a rough draft of a lethality description. I felt guilty about arguing about testing without moving forward. So, I banged this next one out and am putting it on the wire early so folks can through some stones:

Requirement 3: Lethality

Threshold: Bare Gelatin


Penetrate at least 30 cm into bare gelatin conforming to the FBI Test 1 description with the average width of the permanent cavity at least 2. cm over at least 10 cm using a bullet design conforming to the NATO interpretation of Hague and Geneva conventions.

Rationale: This threshold requirement makes the bullet lethality at least equivalent to the 7.62X51 M80 round in the first 30 cm of penetration.

Discussion: To be filled in...

Objective 2: Robust wound channel

Penetrate at least 50 cm into bare gelatin with the damage channel being greater than 2.0 in maximum dimension within 10 cm of the entry.

Rationale: Specifiyng the width of the damage channel at 10 cm means that the channel will almost certainly be starting to open at about 5 cm into the gelatin block

The FBI Test 6 spelled out here - http://greent.com/40Page/general/fbitest.htm

Discussion: While tumbling of the bullet is undoubtedly the mechanism through which the wound channel will grow in dimension, describing the desired effect gives the inventive minded options to attain that effect.

[stanc]

Frankly, I would welcome some neat pictures of holey metal and splashed gelatin, but I cannot in all honesty advocate those tests until we're pretty sure the rest of the story holds water.
I don't have a clue what you mean by that. The idea is to determine 6.5 Grendel performance vs 5.56 and 7.62 NATO, not to write a novel. :confused:

LR1955 has indicated more than his personal views in the questions and challenges he gave us when he started Part I of this thread. He correctly points out that probability of hit is a major factor. He also tells us that flatter trajectories inside of 500 meters are an important factor in improving probability of hit by the normal infantryman. These won't be resolved by the suggested tests.
Huh? Hit probability can only be determined via testing.

We're working toward formalizing the discussion in a format similar to that normally employed in articulating requirements for a capability. One of the advantages is that working through the document helps us be sure we've captured the less obvious, but still critical, issues that go into making a particular concept useful in the acquisition sense. Even more important, we get to identify the things that are most critical so that those who have the resources and are willing to expend them will have better confidence that their tests and analyses have meaning.
And a requirements document will certainly be valuable, during the presentation phase.

It isn't needed (nor will it help) to determine what performance that loadings with currently-available bullets will deliver. That can only be discovered by shooting.

The whole point of this thread is to develop that story by:


describing the needs and goals,
articulating the needs and goals in a way that allows analytic testing of alternative solutions, and
defining physical tests to determine which, if any, of the alternative solutions meet the threshold needs.


Once we've got the major details nailed down, I will become part of the choir singing for tests...
Although you're doing the "story" bit, again, ;) the problem seems to be that you're concerned with the quest for the best possible cartridge, whereas John and I were discussing just finding out where the intermediate caliber concept stands in the form of 6.5 Grendel.

The two ideas are not mutually exclusive. It's quite okay for somebody to test 6.5 Grendel and have somebody else create a requirements document during the same time frame. For that matter, having 6.5 Grendel test data could be of assistance in formulating the requirements document. Otherwise, you're establishing requirements without any real idea if the goals are achieveable.

[JASmith]

...you're establishing requirements without any real idea if the goals are achieveable.
On this point, one must keep in mind that the key to a successful requirements document is that the goals must be achievable.

Neither of us has the resources to do the testing. Others are welcome to test and I would be more than happy to advise (and observe and help if in a location I can get to...)

Let's note that we agree on the end goal and bring the requirements discussion to a good place. I know it is needed and is imminently doable in the absence of new tests.

[stanc]

Here's a rough draft of a lethality description. I felt guilty about arguing about testing without moving forward.
Yeah, well...I really should have taken my posts about 6.5G testing to a different thread. It's just too eeeeeasy to reply to someone off topic in the same thread. :o

So, I banged this next one out and am putting it on the wire early so folks can through some stones:

Requirement 3: Lethality

Threshold: Bare Gelatin


Penetrate at least 30 cm into bare gelatin conforming to the FBI Test 1 description with the average width of the permanent cavity at least 2. cm over at least 10 cm using a bullet design conforming to the NATO interpretation of Hague and Geneva conventions.

Rationale: This threshold requirement makes the bullet lethality at least equivalent to the 7.62X51 M80 round in the first 30 cm of penetration.
For equivalent performance, shouldn't the wording be something like "...the average width of the permanent cavity at least 2.0 cm, over a distance of 20-35 cm into the gel block..." ?

Objective 2: Robust wound channel

Penetrate at least 40 cm into bare gelatin with the damage channel being greater than 2.0 cm in maximum dimension within 10 cm of the entry.

Rationale: Specifing the width of the damage channel at 10 cm means that the channel will almost certainly be starting to open at about 5 cm into the gelatin block.
This seems like an unrealistic expectation to me. The fastest yawing FMJBT bullet appears to be the 5.45x39 M74, which has onset of yaw at ~7cm. IIRC one of Fackler's articles, the reason that happens is imbalance caused when the lead plug in front of the steel core flows assymetrically upon impact. Since lead is verboten for the next generation military bullets, it's questionable if yaw can be made to happen at 7cm, let alone 5cm.

Judging by Fackler's wound profile drawings, it looks as if the best that might be achieved -- with FMJ bullets having lightweight material (such as aluminum) in the nose, to shift CG rearward -- is onset of yaw at ~10cm, as with the .303 MkVII round.

FWIW, non-fragmenting FMJ rifle bullets typically penetrate about 60cm into gelatin, so specifying 30-40cm is hardly a challenge.

[JASmith]

:)Concur -- we need tests!!:)


...it's questionable if yaw can be made to happen at 7cm, let alone 5cm.

Judging by Fackler's wound profile drawings, it looks as if the best that might be achieved -- with FMJ bullets having lightweight material (such as aluminum) in the nose, to shift CG rearward -- is onset of yaw at ~10cm, as with the .303 MkVII round...
Kinda looks that way to me too. On the other hand, the words we're referring to are in the objective statement. Hence we are allowed to push the edge of do-ability since no harm accrues to a contestant for falling short -- unless a competitor finds a way to make it happen!

The project would be in real trouble if we write a threshold statement that no solution could meet! So, the rule of thumb is:

Threshold = doable within reason while satisfying all the other thresholds.
Objective = can be a stretch if remotely in reach. These help spell out what we really want but aren't sure they're doable. (Shouldn't write them if we know they are out of reach!)



FWIW, non-fragmenting FMJ rifle bullets typically penetrate about 60cm into gelatin, so specifying 30-40cm is hardly a challenge.
I think the 40cm in the objective was a typo. I was thinking of a half-meter, which is a tad more than two feet. Have corrected the statement in post #18 above.

The real question is -- can we identify a payoff for penetrating deeper than 50 cm?

[JASmith]

Returning to post #18 of this thread, we can infer that proving the superiority of one caliber/bullet/cartridge poses a significant challenge when we consider the posts by bwaites: Stopping power by Caliber (http://www.65grendel.com/forum/showthread.php?558-Stopping-power-by-Caliber) and http://www.65grendel.com/forum/showthread.php?562-Stopping-Power-by-Caliber-Part-2.

Consider this extract of percentage of one-shot stops:


25 ACP 30%
22 Rim 31%
32 ACP 40%
380ACP 44%
38 SPC 39%
9mmLug 34%
357Mag 44%
40 S&W 45%
45 ACP 39%
44 Mag 59%
Rifle 58%
ShotGn 58%
It's hard to get better than the 50-60% suggested by the rifle and shotgun statistics.

This data may suggest we recast the gelatin test to reflect the performance of a the FMJ 9mm at the muzzle as the threshold and that of the 7.62X51 M80 as the objective. The range(s) we would require these degrees of lethality also need to be discussed.

This combination would allow some differentiation based on the statistics presented and possibly avoid an arbitrarily high threshold on cartridge lethality.

[stanc]

Returning to post #18 of this thread, we can infer that proving the superiority of one caliber/bullet/cartridge poses a significant challenge...
Yes, indeed it do. I don't know if quantifying gel test results can even be done satisfactorily.

...consider the posts by bwaites: Stopping power by Caliber (http://www.65grendel.com/forum/showthread.php?558-Stopping-power-by-Caliber) and http://www.65grendel.com/forum/showthread.php?562-Stopping-Power-by-Caliber-Part-2.

Consider this extract of percentage of one-shot stops:


Rifle 58%

It's hard to get better than the 50-60% suggested by the rifle and shotgun statistics.
IMO, his one-shot-stop % is a rather meaningless figure.

A better measure is his % actually incapacitated by one shot:


Rifle 80%

This data may suggest we recast the gelatin test to reflect the performance of a the FMJ 9mm at the muzzle as the threshold and that of the 7.62X51 M80 as the objective.

This combination would allow some differentiation based on the statistics presented and possibly avoid an arbitrarily high threshold on cartridge lethality.
I think I see your reasoning, but it seems to me that 9mm FMJ is much too low for threshold. Wound profile of 9mm FMJ is not even as good as that of .30 Carbine, which can easily be exceeded by most military rifle calibers.

FWIW, I consider his stopping power data too flawed -- or at least incomplete -- for this purpose. For one thing, it does not tell us what the difference in performance is between FMJs and JHP/JSP expanding bullets. Since this thread is concerned with military rifle Ball ammo, the numbers for JHP/JSP rounds would have to be deleted, something we can't do with the posted summary.

Also, he does not tell what % actually incapacitated by one shot weren't fatal, which (IMO) would be a far more reliable indicator of effectiveness. Any bullet will "incapacitate" by killing; it's when a torso hit is not immediately fatal that incapacitation becomes important.

[JASmith]

...A better measure is his % actually incapacitated by one shot:


Rifle 80%...Any bullet will "incapacitate" by killing; it's when a torso hit is not immediately fatal that incapacitation becomes important.
The qualifier for "actually incapacitate" is that the shot hit the head or torso. Consider the .25 ACP statistic for example:

% actually incapacitated by one shot (torso or head hit)- 49%
This tells me that a hit in the torso or head takes one out of action about half the time or better, even with a pipsqueak caliber/cartridge. The issue is how the statistics were derived.

The questions you raise are best resolved by sending them to the author of the study. He might even have a soft spot where things Grendel are concerned...

In the meantime, this is the best set of statistics I've seen in the open literature.

The pucker factor for a 7-yard shot is a lot greater than it is for a 500 meter shot. So, in my view, the 9mm (or M1 Carbine) equivalent threshold is best applied at some distance from the shooter.

So, struggling for an understandable description, one could say that: "The wound channel for a gel target hit at 500 meters must be at least as large in major cross-section and depth as that of a 9mm FMJ hitting the same block 1.5 meters from a block of the same specifications."

I would happy to replace "M-1 Carbine" for "9mm" in the above.

[stanc]

The qualifier for "actually incapacitate" is that the shot hit the head or torso.
True. That's why in my conclusion I said "he does not tell what % actually incapacitated by one shot weren't fatal, which (IMO) would be a far more reliable indicator of effectiveness."

Consider the .25 ACP statistic for example:

This tells me that a hit in the torso or head takes one out of action about half the time or better, even with a pipsqueak caliber/cartridge. The issue is how the statistics were derived.
Precisely my point. He doesn't differentiate between "incapacitation" by killing and non-fatal incapacitation.

The questions you raise are best resolved by sending them to the author of the study.

In the meantime, this is the best set of statistics I've seen in the open literature.
That may be, but it doesn't overcome the flaws in the data he presents. Remember, GIGO.

The pucker factor for a 7-yard shot is a lot greater than it is for a 500 meter shot. So, in my view, the 9mm (or M1 Carbine) equivalent threshold is best applied at some distance from the shooter.

So, struggling for an understandable description, one could say that: "The wound channel for a gel target hit at 500 meters must be at least as large in major cross-section and depth as that of a 9mm FMJ hitting the same block 1.5 meters from a block of the same specifications."

I would happy to replace "M-1 Carbine" for "9mm" in the above.
No need.

P.S. I do think inserting 9mm (or .30 Carbine) performance into the requirements is likely to cause confusion in those reading a document about potential replacements for 5.56 and 7.62 NATO.

[JASmith]

...I do think inserting 9mm (or .30 Carbine) performance into the requirements is likely to cause confusion in those reading a document about potential replacements for 5.56 and 7.62 NATO.
You just hit on part of the reason I mentioned the M-1 Carbine as a possible threshold -- as you helped us understand, this "little guy" actually does tumble and you've sent us a neat picture of the permanent cavity in gel.

So, as in the earlier draft, we ask that the major cross section of the wound cavity be at least a specified dimension. The FMJ bullet tumbles, so the length of the bullet becomes the basis for the threshold. The Speer 110 gr TMJ 30 Carbine bullet is shown as having a length of 0.676" in the JBM "Lengths" Library. So, we take approx 90% of the length and require that the maximum width dimension be at least 0.6" on average over at least (a guess) 5" of the permanent gel cavity.

We'll need to mensurate the picture you posted but you get the idea...

This gives as a measurable quantity that is based on arguably questionable statistics and actual performance of a surrogate.

I wonder if Bill can approach the author to get more detail about the statistics?

[noone]

I find the one shot stop statistics quite interesting. I think they are most useful for those who only plan on firing one shot. I would like to find some statistics on two or three shot stops, and some statistics on shot placement and find out what those tell us.

If 95% of firearms stop someone with two well placed shots, they it would stand to reason that using the firearm that allows you to get those two well placed shots placed properly as quickly as possible (like a 32 auto, or 9mm VS 45 or 44) would be the way to go.

In the end though, I think that people will continue to disagree (bicker or argue sometimes) about which statistic backs up their favorite belief the best.

I'll continue carrying a 45ACP as a primary pistol, with a small backup pistol. For rifle, although I seldom carry one for "self protection" any longer, I think the 6.5 Grendel and it's offshoots loaded with a 120 grain bullet and similar weights will be hard to beat for all round speed for close engagements, actual power on target, long range accuracy and power, and reasonable weight for the system and ammo.

Sure, the 308 has more power, and the 338 has even more than that. And the 5.56 weighs less with a basic ammo load. But as an overall compromise, the Grendel and the 45ACP are hard to beat.