New Army "Caliber Configuration Study"

[cory]

Hasn't someone already run ballistics to help illuminate the question of whether .338 can do as well as .50 cal?

I was referring to it's terminal performance on vehicles and light armor.

Hasn't someone already run ballistics to help illuminate the question of whether .338 can do as well as .50 cal?

Nincomp I was referring to the end game scenario, but I completely agree with what you just said. The biggest question here is, can the .338 be effective enough against vehicles and light armor to replace the 50 cal.

I don't think so, but I have been wrong before. The bigger projectile of the .50 gives more room for things like HE.

JASmith, I think that the proposed .276 Penderson and the .280 British (the 7x43mm version) could have been GPC's. They were intended for individual weapon and LMG use. I don't know if they were to be used in the MMG role, however.

Ironically, the Japanese had the 6.5mm Arisaka and the Italians had the 6.5 Carcano, but both initially used round-tipped bullets which had poor terminal ballistics. They both decided to move up to to a larger caliber. I do not know if the Japanese reevaluated the 6.5 Arisaka after switching to the pointed bullets which would yaw after impact.

[cory]

Nincomp I was referring to the end game scenario, but I completely agree with what you just said. The biggest question here is, can the .338 be effective enough against vehicles and light armor to replace the 50 cal.

With the adoption of a GPC we'd see a LMG and MMG system. The new LMG would fall somewhere in between the current LMG and MMG. Exceeding the requirements of the current LMG and not quite being suited for all the requirements of the current MMG. The new MMG would meet all the requirements of the current 50 cal HMG while being able to meet the mission requirements of the current MMG that the new LMG isn't AS suited towards (Vehicle Mount).

I realized that I did not address this part of your post. As I understand it, a GPC would only replace the MMG for dismounted soldiers. The 7.62x51 would stay in service for mounted installations, at least for a while (since we already have a large number of 7.62 MG's and ammunition). The 7.62 might eventually be replaced by by something more powerful, like a .338, but that is a separate argument.
One major issue will be the performance of the 7.62 if the military insists on lead-free ammo. The chambers for the 7.62x51 (and the 5.56x45, for that matter) were designed for lead/copper bullets which do not have long ogives sticking out of the case. This not only prevents longer, more aerodynamic bullets, but it means that more of the longer lead-free bullet will need to be crammed into the case, reducing the volume for powder. *

It would not surprise me if MG terminology and use gets more confusing, but maybe not. This is what I see likely:
LMG - GPC: carried by dismounted troops
MMG - 7.62x51: mounted MMGs Note: might eventually be phased out, possibly by a .338.
HMG - .50 Cal**
GPMG - ? Depends on your definition. Possibly none.
"Holy Crap" - minigun

As to 7.62x51: It would not qualify as a GPC, given Tony Williams' definition. When it was introduced, "Universal Cartridge" would have been closer. To be more accurate, "Universal Cartridge except for the .50 BMG, for Heaven's Sake," but that is a bit wordy.


* If a new lead-free bullet is to weigh nearly the same as M80, it will be longer. The most likely materials, steel and copper, are less dense that lead. Search for images of "M80A1" and look at the 147grain variant. For 5.56x45, see the M855A1

** Sometimes, bigger is better (despite what I tell my Wife)

See post #186 above.

That post is not enough to answer the question.

Can you expand a bit?

[stanc]

Then how was the 7.62 intend to be a "GPC", by your logic?

See post #186 above.

The GPC idea seems to be an LMG that could perform in the same capacity as the current MMG where the dismounted Grunt is concerned.

The general idea is that the GPC would have the effective range of the 7.62x51 MMG and replace the 7.62x51 MMG for the dismounted "Grunt." The GPC ammo would be lighter than linked 7.62x51 per round and (hopefully) be used in lighter LMGs.

The GPC would also be used to extend the reach of a soldier's individual weapon to permit effective fire at longer ranges. This would also permit more effective suppressive fire, permitting the LMG to maneuver, among other things.

Part of the genesis of the GPC stems from the experience of Afghanistan*, where many engagements occur beyond the effective range of the 5.56. One veteran said that everyone except the MMG gunner and maybe a Designated Marksman could only twiddle their thumbs. Even in locations where our troops could easily maneuver close enough to effectively use their rifles, the attackers would have had enough time pack up and leave.

Tony has written an interesting paper which is much more detailed than my summary.

http://www.quarry.nildram.co.uk/The%20Next%20Generation.htm

* Many of the unstable parts of the world, especially in the Middle East, have terrain where long-range fire would be expected.

[cory]

Then how was the 7.62 intend to be a "GPC", by your logic?

[stanc]

Wait at what point did the Army want to replace the 50 cal Browning with a 7.62???

AFAIK, nobody has ever been silly enough to advocate that 7.62 NATO replace .50 BMG.

[cory]

"No No and No" what?

IIRC, it started with US Army Ordnance near the end of WWII. What became 7.62 NATO was intended to be a GPC, for infantry rifle, automatic rifle, sniper rifle, and general purpose machine gun.

Tony and company have revived the GPC concept, but with a smaller and lighter cartridge.

I don't believe they have the same intent, but I could be wrong.

Wait at what point did the Army want to replace the 50 cal Browning with a 7.62???

[stanc]

No No and No.

"No No and No" what?

Where did the notion of one rifle round for all of the Infantry come from?

IIRC, it started with US Army Ordnance near the end of WWII. What became 7.62 NATO was intended to be a GPC, for infantry rifle, automatic rifle, sniper rifle, and general purpose machine gun.

Tony and company have revived the GPC concept, but with a smaller and lighter cartridge.

[cory]

The original premise of the notional GPC was to replace all 5.56mm and 7.62mm weapons -- including GPMGs/MMGs -- in infantry units, thereby replacing a two-caliber system with a single caliber. That would have made "General Purpose Cartridge" an accurate description.

If 7.62 is replaced by .338 for GPMGs/MMGs, with other weapons using a different caliber, then the infantry would still have a two-caliber system. That makes the "GPC' something less than a GPC.

No No and No. Where did the notion of one rifle round for all of the Infantry come from? This idea falls in the same realm as the 90-100% efficient internal combustion engine. While it'd be an amazing Round/Engine it just isn't possible.

The GPC idea seems to be an LMG that could perform in the same capacity as the current MMG where the dismounted Grunt is concerned,

What we have now is the following system of machine guns.

LMG
MMG
HMG

With the adoption of a GPC we'd see a LMG and MMG system. The new LMG would fall somewhere in between the current LMG and MMG. Exceeding the requirements of the current LMG and not quite being suited for all the requirements of the current MMG. The new MMG would meet all the requirements of the current 50 cal HMG while being able to meet the mission requirements of the current MMG that the new LMG isn't AS suited towards (Vehicle Mount).

[stanc]

That would not alter the fact that a single cartridge replacing 5.56mm and 7.62mm in all infantry rifles, DMRs and LMGs in the company would still be a GPC as far as I'm concerned.

The original premise of the notional GPC was to replace all 5.56mm and 7.62mm weapons -- including GPMGs/MMGs -- in infantry units, thereby replacing a two-caliber system with a single caliber. That would have made "General Purpose Cartridge" an accurate description.

If 7.62 is replaced by .338 for GPMGs/MMGs, with other weapons using a different caliber, then the infantry would still have a two-caliber system. That makes the "GPC' something less than a GPC.

Also, when you throw in Royal Marines, we're talking about a totally different organization with its own unique force structure, selection and training, and doctrine. Royal Marines are a rapid deployment multi-faceted commando unit with its own peculiarities. Take a look at their MTO&E to get a better idea of what I'm talking about:



The closest thing I can relate to it would be a maritime Ranger Regiment, with organic slice elements mixed in that would normally be part of a Marine Brigade, with Maritime Special Forces (SBS) at the upper end of the short leash. For those in the US that might think they're just British Marines, not really.

What really sets them apart is the selection and training process, the MTO&E, and the OPTEMPO of their unit training and deployments. It's a very exclusive organization with extremely difficult initial entry standards to pass through. Attrition is very high, and not all kids get an A for effort. Most will pack their bags and leave within the first few months, and the course is 32 weeks for enlisted trainees.

The closest US comparison would be 75th Ranger Regiment, if you tailored Ranger Regiment towards maritime operations. The mindset of guys from both organizations is frighteningly similar. An entry-level soldier from both units can be counted on to take the fight to the enemy with aggression and competence, with very high standards of junior leadership experience and training to manage him. That is at odds with much of the rest of the military.

As to the GPC concept, it's dead on arrival for a number of reasons, endurance being the most important to actual fighters, and inappropriateness of capability for many of the combat arms duty positions, never mind all the rear echelon support personnel.