I do not like the 5.56mm/7.62mm NATO mix we run now. It works, but I think we could do better. Caveat being that before I blew the cash on replacing them, I’d demand that real research be done to either validate my ideas or prove me wrong.

I think you’re right. I believe that you need a heavier machine gun round also but a longer range round is necessary for the individual soldier. A lot of this can be obtained by making the bullet more streamlined without raising the weight too much and using new case design. The link I posted earlier has a lot of examination of this.

The idea is seductive, one related weapons system to simplify logistics and training, and one cartridge, and everyone tries it, and everyone abandons it. Even the U.S. with the laughable “M-14 for every role”.

Canada tried it with the C1(FN FAL) rifle, and C2 (FN FALO Automatic Rifle), and it might have worked with an intermediate calibre, but the C2 was too light for 7.62, and despite the doctrine, GPMGs got borrowed from the Support Company and put down to the platoon level almost immediately.

The Russians tried it with the AK rifle and RPD/RPK. but whenever they actually fought (Afghanistan/Chechnya), the PK/PKM would show up in the infantry squad/section.

The Brits tried twice, first with the EM-2, for use by the Infantry Section/Squad, with a belt fed Bren Gun derivative for the support Company and vehicle roles, but Studler put paid to that. Later, they tried again with the SA-80 program, but that failed with the poor quality of the system, and even then, like the Russians, whenever the Brits actually went into combat, L7 GPMGS suddenly and mysteriously appeared at section level.

The Marines are trying something similar again, and we will see.

The Chinese are also trying, but they are producing cartridges with different loadings for different purposes. A bad idea in my opinion, since Pvt. Snuffy (Pvt. Chin?), will end up stuffing the heavy ball machine gun round in his rifle, out of ignorance, stress induced error, or because that is what showed up in the combat re-sup with predictable results. The logistics of a common round size and common large scale packaging (i.e. pallet size), are desirable even with different loadings, so I can see the appeal.

I did suggest in a comment elsewhere, that this approach might work if the weapons were made more adjustable. The previous Japanese service rifle was chambered for 7.62 NATO, but the Japanese used a lighter bullet and charge in their cartridge, but the gas regulator had a setting for using the NATO round, by venting more gas to the atmosphere so the heavier round didn’t damage the gun. A similar approach might work for the Chinese. Have a gas regulator that would vent off more gas if a heavy ball machine gun round needed to be used in a rifle, for example.

On the other hand, I have to agree with you that increasing the 5.56mm by too much would make it ineffective as an individual weapon, and a 6.8 SPC or whatever , would not be nearly powerful enough for support use. Given the relative un-importance of the individual rifle in modern combat, I think the two cartridge solution is here to stay.

I think the 5.56mm is fine as it was originally intended, for use as an assault rifle cartridge, mostly in Western Europe, against the Soviets, and with a maximum effective range (2-300 meters),dictated by terrain and iron sights.

However, lately, doing a lot of counter-insurgency, in arid and desert terrain, with the almost universal adoption of optics, practical effective range is now more than 2-300 meters, and the power and lethality is being called into question, and an increase in size and power is probably justified. Unfortunately, the current 6.8 solutions are constrained by keeping the costs down, so keeping the same magazine well, receiver length etc, and I am not sure the juice is worth the squeeze.

Also, I have to admit, the logistics advantages are mostly theoretical. Small calibre small-arms ammunition is a small fraction of logistics, in terms of weight and volume. Even if you managed to make one cartridge do it all, you would still have different packaging and different loadings. Belted ammo for MGs (mixed ball and tracer, or mixed AP, API and tracer), rifle ammo (cartons or bandoleers of stripper clips), sniper/match ammo, etc. etc. and that would be dwarfed by the quantities and varieties of grenades, mortar ammo, HMG and auto-cannon ammo, Automatic grenade launcher ammo, radio and NVG batteries etc. etc. etc.

Nobody had any difficulty in WWII/Korea providing the front line troops with the various ammo required back then, even with coalition warfare and the non-standardization prior to NATO. Even the Japanese with their more than on kind of 7.7mm and Italians with similar problems managed. The only issue I ever heard of was the Germans not able to deliver 7.92 Kurtz after initial allocations, but that was due to strategic supply and manufacturing, not to the inability to do the combat logistics.

Despite all the lobbying for the 6.8, and the new telescoped semi-caseless concept,I think economics and logistics will mean that we will have 5.56mm and 7.62mm for the foreseeable future. We will add .338 Lapua and perhaps a couple of other varieties of grenade cartridge/small auto-canon cartridge, but until the phased plasma rifle in the 40 watt range shows up, what we have is “good enough”.

All too much of what goes into the decision-making process in this regard is based on theory and supposition. There’s very little real knowledge or data to back anything up–From the data we have, you could argue that the 5.56mm/7.62mm NATO dual-caliber solution we have today is flawed, or you could argue that it is nearly perfect.

What I can say, from the evidence, is that every time we’ve tried the unified cartridge idea, it’s been blown up by reality. The 7.62mm NATO was supposed to be the one cartridge that did it all, from MG down to the submachinegun PDW role. It manifestly did not, and we got our asses handed to us in the dense jungles of Vietnam. So, they tried for another solution, the 5.56mm, and while it was acceptable as an individual weapon cartridge, it was not workable for the support role. So, by accident, we recapitulated the German experience with the StG44 and MG42, and the Soviet experience with the 7.62X39 and 7.62X54R families. Dual-caliber is what practice teaches us is necessary, and none of the unified cartridge ideas have really worked worth squat down on the line. No matter which direction we’ve approached it from…

While I think the 5.56mm is flawed, and not lethal enough, I also think that if you go much past it in terms of power that you’re going to start having problems actually using the damn thing in individual weapons. Likewise, I feel like the 7.62mm NATO is underpowered for its role in the support weapons, and would prefer us to go to something a bit more substantial–But, not that freakin’ .338 Lapua Magnum. That’s a bit much, to my mind.

And, of course, I’ll freely admit I can’t back any of that up with data. Nobody can, because nobody has really bothered to do a lot of the fundamental research, and frankly, we really don’t know what the hell is going on in direct-fire small unit combat these days.

All too much of the thinking in this area is specious, poorly thought-out, and badly sourced. There’s a lot of magical thinking about things, and mis-attribution of effects. If you really wanted to answer these questions, you’d have to wire a unit for sound, monitor it in a real action, then recover the enemy bodies for analysis. Do that, and you might begin to get to actual ground truth, but anything short of that…? You’re gonna be doing mostly wishful thinking.

I used to think we had a really good handle on what goes on in battle, but after a tour working as an observer/controller at the NTC, and observing combat from the vantage point of the divisional HQ for the 101st Airborne for a year, what I’m convinced is that we mostly really don’t.

http://quarryhs.co.uk/AGWpubs.html