New Army "Caliber Configuration Study"

[BluntForceTrauma]

To be technical, 5.45 DOES have a small amount of lead.

The reasons for steel-core at the end of WWII are inconclusive. I would tend to think it was due to a shortage of raw material, rather than rigorously examined technical improvements.

It could well have "reduced the effectiveness" of small arms. Could be at that point the powers that be realized small arms were a relatively small factor in the overall killing and wounding equation, and that as long as it goes bang it's good enough when resources are scarce.

Again, the Russian use of steel core is to gain a certain amount of penetration, all while maximizing their use of raw materials. As such, they, again, exhibit cooly rational thinking to gain a military, albeit strategic advantage, and it has nothing to do with environmentalism.

If you want to compare apples to apples, and put up a steel-core 6.5 Grendel round against their steel-core 7.62x54R, that's a more fair comparison than hobbling the 65G to a lead-free bullet vs. Russian lead-cored, as we were discussing above.

John

[stanc]

To be technical, 5.45 DOES have a small amount of lead.

Yes, as do most conventional steel-core bullets. Can we call them "light green" bullets?

The reasons for steel-core at the end of WWII are inconclusive. I would tend to think it was due to a shortage of raw material, rather than rigorously examined technical improvements.

Actually, the reasons are not at all inconclusive. In the European theatre, the enemy had light armored vehicles, and there was much urban combat. Steel-core, .30 M2 AP had significantly better "hard target" penetration than lead-core, .30 M2 Ball, but was just as effective against personnel. Steel-core bullets cost a bit more than lead-core, but are typically better "general purpose" rounds.

I don't recall if it was this forum or the old one, but Bill Alexander once said his preference for a 6.5 Grendel military load would be steel-core.

It could well have "reduced the effectiveness" of small arms. Could be at that point the powers that be realized small arms were a relatively small factor in the overall killing and wounding equation, and that as long as it goes bang it's good enough when resources are scarce.

I'm pretty certain that conservation of a strategic material (i.e., lead) was the reason nations switched from lead to steel for core material of ball projectiles. But, if steel-core bullets were actually less effective than lead-core bullets, how do you explain that (lead-core) M80 Ball was originally intended to be used solely for training, while (steel-core) M59 Ball was reserved for combat?

Again, the Russian use of steel core is to gain a certain amount of penetration, all while maximizing their use of raw materials. As such, they, again, exhibit cooly rational thinking to gain a military, albeit strategic advantage, and it has nothing to do with environmentalism.

Okay. I agree they're not concerned with environmentalism. However, if they're as pragmatic as you say, would they be using steel-core bullets if such had poor terminal effects?

If you want to compare apples to apples, and put up a steel-core 6.5 Grendel round against their steel-core 7.62x54R, that's a more fair comparison than hobbling the 65G to a lead-free bullet vs. Russian lead-cored, as we were discussing above.

??? I'm aware of no comparison being made to lead-core 7.62x54R. The comparison was with steel-core 7.62x54R.

I would be quite willing to have a steel-core vs steel-core comparison. What is the BC and MV of the Wolf steel-cased 100gr FMJ load?

[BluntForceTrauma]

Maybe you're confusing mild-steel cores, which I would guess is a lead-preserving, cost-saving measure (unless mild steel flies and penetrates better than lead FMJs?), and Armor Piercing steel cores, instituted for the specific purpose of gaining a tactical military advantage through superior penetration.

So, to the point, we've agreed the Russians were seeking either a tactical edge via AP or a strategic resources edge via cheap mild steel. Now, is the U.S. military going lead-free because they're coldly seeking a tactical or strategic edge or because they want to be environmentally sensitive? I think I know the answer.

John

[JASmith]

The massive clean-up of DU in Kuwait after Desert Storm and the move away from Tungsten in addition to the almost religious aversion to anything with lead in it supports John's contention.

In point of fact, many of the "greenies" are just as happy if we hobble ourselves this way. They think that less capable weaponry might keep us from getting into a war.

Their problem is that they really don't understand the nature of deterrence. It works ONLY when both a superior capability AND demonstrated will to use that capability exist together. When they both don't exist, one is either bluffing or timid. Either way, trouble is in the works for those who don't understand and have the tools to use deterrence.

[stanc]

Maybe you're confusing mild-steel cores, which I would guess is a lead-preserving, cost-saving measure (unless mild steel flies and penetrates better than lead FMJs?), and Armor Piercing steel cores, instituted for the specific purpose of gaining a tactical military advantage through superior penetration.

No, I'm not confusing the two types of steel-core bullets.

Yes, use of steel for bullet cores is a lead-conserving measure, but everything I've read says that because construction of steel-core bullets is more complex, they cost more to manufacture than lead-core projectiles. Cost differential of the raw materials is reportedly quite small.

Not sure what you mean by "flies better." According to what I've read, steel-core bullets typically are less accurate, but also have higher BC, than lead-core bullets of the same weight.

And yes, mild steel-core FMJs generally have measurably better penetration than lead-core FMJs of the same caliber and weight.

So, to the point, we've agreed the Russians were seeking either a tactical edge via AP or a strategic resources edge via cheap mild steel. Now, is the U.S. military going lead-free because they're coldly seeking a tactical or strategic edge or because they want to be environmentally sensitive? I think I know the answer.

Are you sure?

[COLOR="darkgreen"]...there were three sets of competing requirements.

The Infantry Center expressed a number of performance goals compared to M855:
Improved soft target lethality over M855;
Improved accuracy over M855;
General purpose capability;
Ballistic similarity to M855;
Similar hard target performance to M855;
Optimized for the M4 carbine; and
Reduced flash.

SOCOM was most interested in finding a round that would have significantly better accuracy than Mk262 and be available at lower cost – best, in fact, if one of the other services adopted it, as a SOF-specific round would be purchased out of SOCOM budgets rather than provided by the big Green Army. Other concerns were secondary provided the round could be optimized for the shorter barreled weapons SOF operators were using.

The program manager (PM-MAS) needed to find a solution that was “environmentally friendly” (defined as a lead-free projectile, no tungsten) to meet the Green Ammunition mandate for which they were already funded.

Ultimately, the team came up with a plan that would meet most of the requirements of most of the parties. The design effort would work to the Infantry Center’s basic requirement, with the understanding that SOCOM could take or leave the solution depending on its performance. The solution would have to be “green”, which would justify using the available funding and existing program to do the work, rather than having to go back and justify and fund a new ammunition development program.[/COLOR]

I don't know how to copy the link for the whole article. If you wish to read the complete text, Google "m855a1 development" and it should be at the top of the list. It's an RTF file and the title shows on screen as "In Search of Lethality: Green Ammo and the Developmen..."

[stanc]

They think that less capable weaponry might keep us from getting into a war.

Can you, John, or anyone else provide evidence which shows lead-free bullets are necessarily "less capable" than lead-core bullets?

[JASmith]

Let's not confuse a general statement with specific situations.

Nonetheless, a counter example is: A more capable armor-piercing bullet would have a tungsten carbide core. As has been pointed out, tungsten is viewed as "not green."

[BluntForceTrauma]

Stan, in the green text you quoted above, it states: "The program manager (PM-MAS) needed to find a solution that was “environmentally friendly” (defined as a lead-free projectile, no tungsten) to meet the Green Ammunition mandate for which they were already funded."

Does this not prove my point that environmental concerns came first? M855A1 is lead-free first and foremost because of an environmental mandate. All the rest is simply trying to make the best of it, trying to optimize a "green" bullet. You see why I complain political correctness is placed before military effectiveness?

I'm simply echoing a point you, yourself, have already made. If lead-free bullets are too long to be practical then lead-free should not be mandated. It's a simple matter of the physics of ballistics, a matter of material density. While both have similar form factors, throw a ping pong ball and a golf ball as hard as you can and see which sheds velocity faster.

If it turns out that "green" bullets are the better tactical solution, I'm all for them.

John

[stanc]

Let's not confuse a general statement with specific situations.

I guess that translates as, no, you do not have any evidence which shows lead-free bullets are necessarily "less capable" than lead-core bullets.

Nonetheless, a counter example is: A more capable armor-piercing bullet would have a tungsten carbide core. As has been pointed out, tungsten is viewed as "not green."

Irrelevant. The discussion is about general-issue, Ball ammo, not special purpose loads like AP or HPBT.

[BluntForceTrauma]

Specialized loads might be irrelevant, but you're the one who brought up M2 AP.

We're discussing what bullet and ballistics the 6.5 Grendel needs to match 7.62x54R. And it's unclear to me whether we're comparing 7.62x54R lead-core, mild steel core, or AP.

All this is against the backdrop of what terminal effects the U.S. military requires. The slide show linked in another thread about the development of the British .280 was helpful because it actually listed some of the British requirements: something like penetration of steel helmet at 600m, of 1.5 inches of solid concrete at 100 yards in one shot, of 22" of loose dirt, etc.

Nothing makes sense until the military specifies its requirements, then one begins to design a bullet.

John

[JASmith]

..The discussion is about general-issue, Ball ammo, not special purpose loads like AP or HPBT.

This statement completely misses the point and ignores your earlier comment on why steel core bullets were introduced by the US at the end of WWII.

There is nothing wrong performance-wise with using WC cores in general-purpose bullets. They might, however, be a tad more expensive and are not GREEN.

[stanc]

Stan, in the green text you quoted above, it states: "The program manager (PM-MAS) needed to find a solution that was “environmentally friendly” (defined as a lead-free projectile, no tungsten) to meet the Green Ammunition mandate for which they were already funded."

Does this not prove my point that environmental concerns came first? M855A1 is lead-free first and foremost because of an environmental mandate. All the rest is simply trying to make the best of it, trying to optimize a "green" bullet. You see why I complain political correctness is placed before military effectiveness?

For sure, the environmental concerns came first. And if you wish to argue that "all the rest is simply trying to make the best of it," I won't disagree.

What I take issue with is the notion that "lead-free" necessarily equals "less effective."

I'm simply echoing a point you, yourself, have already made. If lead-free bullets are too long to be practical then lead-free should not be mandated.

I agree that they shouldn't. However, the unavoidable fact is they are mandated, and I fail to see what good it does to complain about it. Wouldn't it be more productive to put our efforts into planning for the reality of the situation?

It's a simple matter of the physics of ballistics, a matter of material density. While both have similar form factors, throw a ping pong ball and a golf ball as hard as you can and see which sheds velocity faster.

Generally, we're talking about no difference in weight between lead-core, steel-core, and lead-free bullets. And since a lead-free bullet will necessarily be longer (and therefore have somewhat higher BC) than a lead-core bullet of the same weight, it is the lead-core bullet which will lose velocity faster. Why would you want that?

[stanc]

Specialized loads might be irrelevant, but you're the one who brought up M2 AP.

Yes, but I brought it up because it's an example of an effective, steel-core round which was used as the general-purpose, general-issue load for US troops.

We're discussing what bullet and ballistics the 6.5 Grendel needs to match 7.62x54R. And it's unclear to me whether we're comparing 7.62x54R lead-core, mild steel core, or AP.

Why??? I've said more than once the comparison has been with 7.62x54R steel-core Ball. I've never so much as mentioned comparing 7.62x54R lead-core Ball, let alone AP. :confused:

Nothing makes sense until the military specifies its requirements, then one begins to design a bullet.

If nothing makes sense until then, why do some people keep insisting 6.5 Grendel should be adopted by the military?

[BluntForceTrauma]

M2 AP was designed as armor piercing, but was adopted by the troops as general-purpose because of its penetration performance on a variety of barriers. If one wants to specify an AP round as a general-purpose round, I'm cool with that. I'd probably be happy with a copper and carbide steel GP round.

There are many 7.62x54R bullets. Which one is the mild-steel core load, the standard PKM load, to which we should compare?

Regarding your point that a lead-free bullet, by virtue of its length, has a higher BC, is something I didn't realize. Could be my understanding of ballistics is shaky (ping pong balls vs golf balls?). I thought material density also factored into BC, in the sense that if form factors are equal, the bullet with a higher material density has a better BC. Conversely, a bullet of a lesser density needs to be longer to have the same BC as a bullet of higher density. This is why I postulated that a 108gr lead-free bullet in the 65G case might be too long to be practical to match 7.62x54R.

John

[bwaites]

Not sure what you mean by "flies better." According to what I've read, steel-core bullets typically are less accurate, but also have higher BC, than lead-core bullets of the same weight.
."

Huh? Steel core bullets in the same form factor as lead core bullets will have a LOWER BC than the heavier lead core bullet. If you maximize the optimum shape for two bullets of the same weight, the denser bullet will always win on BC.

[stanc]

Huh? Steel core bullets in the same form factor as lead core bullets will have a LOWER BC than the heavier lead core bullet.

That's true. But, I specified the bullets being the same weight.

If you have two bullets of the same weight, same ogive, same boattail, but one is longer due to lower density core material, will it not have a higher BC?

[stanc]

There are many 7.62x54R bullets. Which one is the mild-steel core load, the standard PKM load, to which we should compare?

The one usually used is LPS Ball. It's what is most commonly found in the US, and AFAIK the type most likely to be encountered in places like Afghanistan.

I'm told the LPS was superseded in Russian service late in the 20th century by the ST-M2, which was in turn succeeded by the 7N13. IIRC, all three weigh ~148 grains, and look virtually the same. The main difference is internal, with the LPS and ST-M2 having a blunt steel core, whereas the 7N13 has a pointed (and hardened) core.

I'm not 100% certain, but because of the small air gap in the tip, I think the sectioned bullet is the ST-M2. Early production LPS bullets have a silver tip like the one on the far left.

MV and BC data is publicly available for the LPS, which is undoubtedly why it's used for such comparisons. I've never seen any numbers for the 7N13.

Regarding your point that a lead-free bullet, by virtue of its length, has a higher BC, is something I didn't realize. I thought material density also factored into BC, in the sense that if form factors are equal, the bullet with a higher material density has a better BC. Conversely, a bullet of a lesser density needs to be longer to have the same BC as a bullet of higher density.

That's mostly my understanding, too, except that sectional density (SD) is a factor in determining the BC. For example, the SD of two 150gr .30-caliber bullets will be the same, even if one has a lead core, and the other has a steel core. As you note, the lower material density of the steel-core bullet causes it to be longer. The greater length, combined with the same sectional density, effectively makes the steel-core projectile more streamlined than the lead-core bullet (assuming the same ogives and boattails on each), and therefore gives the former a higher BC.

This is why I postulated that a 108gr lead-free bullet in the 65G case might be too long to be practical to match 7.62x54R.

Yeah. While at dinner, I got to thinking about your earlier posts, and realized there would be a problem "going green" when the lead-core bullets a cartridge uses are already at or near the upper limit on practical bullet length. I don't know that there's anything to be done about it, though, other than accepting somewhat less ballistic performance than you would prefer...or going to a bigger caliber. Here are calculated bullet weight and BC figures for the 5.45mm 7N6 scaled up:

Dia. ----- Wt. ---- G7 ---- G1

.220" -- 53.5gr -- .168 -- .327
.224" -- 56.5gr -- .173 -- .337
.243" -- 72.1gr -- .188 -- .367
.257" -- 85.3gr -- .199 -- .388
.264" -- 92.4gr -- .204 -- .398
.277" -- 107gr --- .214 -- .417
.284" -- 115gr --- .219 -- .427
.308" -- 147gr --- .238 -- .464

( Adapted from http://forums.delphiforums.com/autogun/m...msg=5924.4 )

[nincomp]

Huh? Steel core bullets in the same form factor as lead core bullets will have a LOWER BC than the heavier lead core bullet. If you maximize the optimum shape for two bullets of the same weight, the denser bullet will always win on BC.

You are correct, assuming that the bullets are of the optimum shape. The problem here is that BC gets better with a better form factor which ends up with longer and longer bullets. When we are looking at magazine-fed weapons, the overall length is limited. This limits the form factor. The perfect example of this is seen when the 6.8 SPC is compared to the 6.5 Grendel. The 6.8 SPC is limited to shorter, lower form factor bullets, so no matter how much the shape is optimized, the BC will be lower than that achievable with the Grendel.

Another good example is the 5.56x45 and the 5.45x39. When they use bullets of roughly the same weight and sectional density (55gr M193 / 53gr 7N6), the 5.45 permits a longer ogive nose, giving a better form factor and BC.

As has been noted by John and Stan, if the performance of a lighter projectile is to match the M80 at long range, the bullet will be too long to fit within the Grendel specs. It is not out of the question that the new cartridge would be the same length as the current 7.62x51 to allow enough powder space and a long-ogive bullet.

In the end, several different parameters need to be balanced, among them are the shape of the bullet and ogive length, bullet weight, case shape and capacity, recoil impulse, etc. Then come the issues of twist rate and bullet stability at low temperatures. When it comes down to it, the goal of Caliber Configuration Study is to figure out what the parameters will be.

[nincomp]

There has been a lot of discussion about Russian bullet construction. Here are some useful links:

5.45x39: http://gunsru.ru/rg_patron_5_45x39_eng.html
Evolution of the bullet: http://translate.google.com/translate?sl...t=&act=url

7.62x39 : http://gunsru.ru/rg_patron_7_62x39_eng.html

7.62x54: http://gunsru.ru/rg_patron_7_62x54_eng.html

I found it interesting that one of the newest bullet types has a lead core: but it is a special issue for reduced richochet. Most of the regular issue ammo has a steel penetrator of some sort, but is was found that they tended to richochet back at soldiers who were performing "special operations in settlements."

While looking for these links, I stumbled across the ATF ruling on the 5.45 7N6 ammo -ouch:
http://www.atf.gov/press/releases/2014/0...ition.html

[Tony Williams]

A comment on bullet design: it does not necessarily follow that a lengthened bullet has a better Form Factor, if the extra length just goes into the shank, leaving the nose and tail profiles the same.

This can be demonstrated by comparing the 7.62mm M80 with the M118 sniper loading (both lead-cored). The M118's FF is almost exactly the same; it has a better BC simply because it's heavier.

Extra length can permit a better FF by allowing a longer, more tapered ogive - but only if the COAL permits this. Which it doesn't in the 7.62x51 (or the 5.56x45, or the .300WM, or the .338LM).

The US has a long tradition of designing cartridges with COALs too short to permit the use of high-BC bullets with long ogives. The 6.8mm Rem is perhaps the most extreme recent example of this - the 6.5mm Grendel is an exception.

One of the key design points of any new military cartridge should be that the specification must allow the use of long-ogive bullets, since they can provide a significant improvement in long-range performance without any extra power, weight or recoil. Apart from slightly longer gun actions and magazines, it provides extra performance at no cost.

Choosing the .338NM rather than the .338LM for the LDAM MMG would be a big step in the right direction.