New Army "Caliber Configuration Study"

[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?

.

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 (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.

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/autog...es/?msg=5924.4 )