I need a .276 Garand POD

Speaking of TFB, he confirms that the CTSAS program (what used to be LSAT) is indeed looking into a 6.5mm round now. Though, of course, they're doing it in precisely the wrong way. They have essentially recapitulated the .260 Remington in plastic cased telescoped form, which is more of a replacement for the 7.62x51mm round but absolutely not the 5.56x45mm round. Look at the size and weight, fer chrissakes! It's the same as the 7.62mmCT, both projectile weight and total cartridge weight- only the recoil is a bit better. Somebody is having a serious error in concept, here, unless there is some requirement that isn't being mentioned. Admittedly, though, they say that they're using the same CT case for 6.5mm as the 7.62mm strictly for convenience during development (using same weapon just by swapping barrels) and it will probably get lighter. Still, it's too powerful despite whatever their 4-dimensional analysis says, so I agree with Nathaniel, there.

Since the trend nowadays is for other-than-lead projectiles (see EPR) that are more structurally rigid than the lead ones, and since they get to start from scratch anyway because they are designing a totally new cartridge, what they should be doing (IMNSHO) is taking the opportunity to design a long, skinny, slightly heavier 5.56mm or 6mm projectile with the same insanely good ballistic coefficients as the 6.5mm ones. (Because the only reason that the 6.5mm rounds have those nice BCs is essentially historical.) Then they'd have their lightweight longer-ranged rifle round, as opposed to what is essentially a marginally-improved AR10 in .260 Remington.

Which, nothing against .260 Remington- I own one- but it sure shouldn't be a service rifle round.
 
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Springfield wasnt making many M1903s in early 1917 iirc annual production from Springfield and Rock Island was about 80,000. The loss of Springfield probably means Rock Island ramps up production and the US adopts the M1917 as per OTL
Right. But the increased production demands placed on RIA are even greater now that SA is hobbled, and the heat-treat problems that were endemic to both arsenals in OTL are magnified. Dozens of maimed recruits gives the M1903 a bad reputation that it never outlives. The British contract rifles being built by Remington, Winchester and Eddystone end up adopted as the M1917 "Enfield", but chambered in the "Cartridge, Ball, 7.62mm (.3in) M1917", to ease logistical issues and consume the vast stocks of ammunition that the Russians defaulted on.
 
but absolutely not the 5.56x45mm round

In other words, you're asking for a concept that has so far been proven to be impossible with our current technological limitations. As I have said before and others in the numerous blog posts have noted, you cannot replace the 5.56x45mm with what we have right now. We'll need a major breakthrough in technology before we can move beyond.
 
Right. But the increased production demands placed on RIA are even greater now that SA is hobbled, and the heat-treat problems that were endemic to both arsenals in OTL are magnified. Dozens of maimed recruits gives the M1903 a bad reputation that it never outlives. The British contract rifles being built by Remington, Winchester and Eddystone end up adopted as the M1917 "Enfield", but chambered in the "Cartridge, Ball, 7.62mm (.3in) M1917", to ease logistical issues and consume the vast stocks of ammunition that the Russians defaulted on.

The Russians contracted for 100,000,000 7.62 rounds according to this website http://www.mosinnagant.net/ussr/US-Mosin-Nagants.asp

Rifle production stats Rock Island made a lot fewer than I thought.
usa-in-wwi-4-huhn-4-638.jpg
 

Deleted member 1487

In other words, you're asking for a concept that has so far been proven to be impossible with our current technological limitations. As I have said before and others in the numerous blog posts have noted, you cannot replace the 5.56x45mm with what we have right now. We'll need a major breakthrough in technology before we can move beyond.
Not really what he said. He's saying that the 6.5mm designs they are looking at now are just filling the role of 762 rather than being a true intermediate round. For historical reasons the 6.5 up until about now is perhaps the ideal intermediate provided it has less power behind it than what is being proposed, but for this future requirement, rather than taking advantage of technologies of the future to develop a modern intermediate the military is picking a proven and older caliber for historical technical reasons; instead of being constrained by the design limitations of the past, a future design that we are working on now should factor in brand new design technologies that change the caliber game entirely.

That said, the Swedes had it about right in the late 19th century when they picked 6.5mm for the 20th century, but for the 21st century the rules of the game have changed due to technology advancements, so we shouldn't keep being stuck to design principles of the 20th century.

what they should be doing (IMNSHO) is taking the opportunity to design a long, skinny, slightly heavier 5.56mm or 6mm projectile with the same insanely good ballistic coefficients as the 6.5mm ones. (Because the only reason that the 6.5mm rounds have those nice BCs is essentially historical.) Then they'd have their lightweight longer-ranged rifle round, as opposed to what is essentially a marginally-improved AR10 in .260 Remington.
Not sure if that is true though, because there is a limit to what length they can make a bullet even with different materials. I've done a unnecessarily large amount of research into artillery shell design based on the ERFB projectiles of Gerald Bull and regardless of the size of the projectile (artillery or rifle bullet) there is a length limitation if you're going to spin stabilize it. That is somewhere in the 5-6 caliber lengths range depending on spin rate and barrel length. I'm seen some cutting edge long range shooting bullet designs and none yet have even gone to 6 caliber lengths despite adding in rotating bands and increasing the twist rate.
For instance:
http://lutzmoeller.net/7-mm/LM-84.php

APFSDS rounds can be much longer because they are fin stabilized, while if you can cast really weird geometries you can make long corkscrew projectiles (done with artillery rounds, but not adopted due to the difficulties of production). So we're still length limited, though we can push the edge of that 6 caliber length max, thanks to stronger materials making smaller caliber rounds more sectionally dense.
 
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instead of being constrained by the design limitations of the past, a future design that we are working on now should factor in brand new design technologies that change the caliber game entirely.

The issue being, we still haven't been able to come up with any new tech that allows us to overcome current limitations. You're basically asking for the (currently) nonexistent and acting like something already exists when it doesn't.


That said, the Swedes had it about right in the late 19th century when they picked 6.5mm for the 20th century, but for the 21st century the rules of the game have changed due to technology advancements, so we shouldn't keep being stuck to design principles of the 20th century.

A round stronger than the Arisaka cannot be said to be good for anything in a "modern" military sense. Far too hot, far too strong.
 

Deleted member 1487

The issue being, we still haven't been able to come up with any new tech that allows us to overcome current limitations. You're basically asking for the (currently) nonexistent and acting like something already exists when it doesn't.
There is the EPR, which due to it's claimed structural rigidity, can arguably be made longer than traditional bullets of say a 6mm caliber without worrying about them breaking in half due to insufficient density/material strength. The 6.5mm caliber was probably the minimum option for the long, heavier bullets with traditional materials/construction techniques.

A round stronger than the Arisaka cannot be said to be good for anything in a "modern" military sense. Far too hot, far too strong.
Not sure if the Carcano blunt nosed round was longer. There is a limit to length and flight stability if you're going to use spin stabilization and you do need to make it aerodynamic to aid flight stability and limit drag loss to energy retention at range. The blunt nosed rounds tumble better on contact with a body and they can fit the most weight for the length due to shape, but their downsides outweigh the advantages in just about all other ways.
 
Ok, ok, that was horribly off-topic anyway. My bad. To clarify:

In other words, you're asking for a concept that has so far been proven to be impossible with our current technological limitations.

Yeah... I'm not sure we're talking about the same thing. That would sort of depend upon your design goals, now, wouldn't it? And the whole point of what I said is that CTSAS is in fact developing new technologies.

As I have said before and others in the numerous blog posts have noted, you cannot replace the 5.56x45mm with what we have right now. We'll need a major breakthrough in technology before we can move beyond.

Well, heck, if YOU said it... ;)

But that's not actually what those blog posts are saying, either, Brother. In fact one is about developing a 6.5mm cartridge for CTSAS service rifles- one that is much less powerful than the one CTSAS developed, which the blogger agreed with me is just too damned powerful for it's intended role. But I (personally) think that even 6.5mm is too big as well, and that's why I'm saying 5.56mm or 6mm. But CTSAS can actually get lighter ammunition while putting a better-BC 5.56mm or 6mm projectile in it, due to the non-lead projectiles' better rigidity as mentioned above a couple of times. So I don't see why we can't get a projectile with a better BC while we're redesigning everything from the ground up, thus reaping incontrovertible benefits with no appreciable down-side.

So I strongly suspect that you are arguing with... er... something that I didn't say.

So, to review: I'm not one of the many people on this forum trying to promote their favorite wildcat intermediate cartridge, here. I have defended 5.56x45mm NATO rather aggressively (ask wiking). And, yes we can replace the 5.56x45mm NATO round if CTSAS works out. And there is no reason to expect that it won't. Because, ya know, they're developing a whole new lightweight polymer cased-telescoped ammunition technology and the weapons for it. And that's what I'm talking about.

If we can produce a high-BC 6mm round that weighs less than current 5.56x45mm with trivially increased recoil, it's hard to defend your statement that we can't replace 5.56x45mm. At this point that's not a "major breakthrough." It works. The government just has to decide what it's priorities are and if they are willing to spend the money, so that an actual field-able weapon and cartridge can be produced.

A round stronger than the Arisaka cannot be said to be good for anything in a "modern" military sense. Far too hot, far too strong.

I agree with you on that, especially the 6.5mm Swedish. Jesus. Which is what I said earlier and you seemed to accuse me of the opposite. ;) Thus all of my confusion above.

We can get a longer-ranged service rifle other ways than just turning the power up to 11 though. Like higher-BC projectiles, as I have been saying.

Not sure if that is true though, because there is a limit to what length they can make a bullet even with different materials.

Granted that sectional density is a factor in the BC equation, but you're overlooking the fact that we have already made high-BC 6mm projectiles out of lead. (Thus the existence of benchrest and other target cartridges like the 6mmPPC.) So almost certainly we can make a 5.56mm one out of copper. Perhaps not long/skinny enough to reach BCs as high as the 6mm and 6.5mm ones while remaining stable, but certainly significantly better. But my (small) doubt about that is exactly why I included 6mm as an option, there- I know it's already been done. Heck, we can keep from making it too long for stability by putting a slug of tungsten in the base to up the sectional density if we have to.

The blunt nosed rounds tumble better on contact with a body...

No, no- exactly the opposite. Spitzer bullets tumble reliably because their center of gravity is dramatically behind their midpoint. So when they meet more than air resistance the ass-end of the projectile tries to flip to become the front of the projectile. Result: a tumble.
 
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Deleted member 1487

No, no- exactly the opposite. Spitzer bullets tumble reliably because their center of gravity is dramatically behind their midpoint. So when they meet more than air resistance the ass-end of the projectile tries to flip to become the front of the projectile. Result: a tumble.
Not from what I've seen:
https://en.wikipedia.org/wiki/6.5×52mm_Carcano
However, the standard Italian service round used an unstable round-nosed bullet with a propensity to tumble, whether hitting soft tissue/ballistic gel or harder material such as bone. See PBS Nova, "Cold Case: JFK",[1] aired 11/12/2013 for range tests.

I know they are supposed to also flatten more to cause more damage, but in terms of the long rounded rifle rounds I gather that they were designed that way to tumble and not penetrate as easily to inflict more damage.

Spitzers have the advantage of aerodynamics and energy retention:
https://en.wikipedia.org/wiki/Spitzer_(bullet)
The spitzer bullet, also commonly referred to as a spire point bullet, is primarily a small arms ballistics development of the late 19th and early 20th century, driven by military desire for aerodynamic bullet designs that will give a higher degree of accuracy and kinetic efficiency, especially at extended ranges. To achieve this, the projectile must minimize air resistance in flight.

Bullets with a lower drag coefficient (Cd) decelerate less rapidly. A low drag coefficient flattens the projectile's trajectory somewhat at long ranges and also markedly decreases the lateral drift caused by crosswinds. The higher impact velocity of bullets with high ballistic coefficients means they retain more kinetic energy.

I agree with you on that, especially the 6.5mm Swedish. Jesus. Which is what I said earlier and you seemed to accuse me of the opposite. ;) Thus all of my confusion above.

We can get a longer-ranged service rifle other ways than just turning the power up to 11 though. Like higher-BC projectiles, as I have been saying.
How about MG rounds? The longer range, heavier round penetration is still pretty useful and necessary.

I'd also argue that in WW2, the 6.5mm Swedish might have been the ideal available round, with the the calibers over 6.5 being too hot and heavy.
 
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Instead of arguing about grams versus grains versus kilo pascals ..... How about debating how soon they could introduce a Garand firing .276 Pederson ammo?
How long would it take to train troops on the new rifle?
How accurate and reliable would it be in early battles?
Which battles?
Which enemy?
Would logistics be able to keep troops sufficiently supplied with .276 ammo.
 

Well, gotta be careful with Wikipedia. It doesn't say the projectile was unstable because it was round-nosed. Just that it was unstable and round-nosed. It is still a rather long projectile, which could add to it's instability. But it's an error to extrapolate that to other round-nosed projectiles.

Seriously, I'm not leading you astray, here.


Spitzers have the advantage of aerodynamics and energy retention:
https://en.wikipedia.org/wiki/Spitzer_(bullet)

True. And they also tumble more reliably. The Carcano loaded with a Spitzer will also tumble better than if loaded with a round-nose, in addition to it's better external ballistics. There is no reason to prefer a round-nosed projectile to a Spitzer, really, unless you're only objective is to make as heavy a projectile as possible for a given length.
 

Deleted member 1487

True. And they also tumble more reliably. The Carcano loaded with a Spitzer will also tumble better than if loaded with a round-nose, in addition to it's better external ballistics. There is no reason to prefer a round-nosed projectile to a Spitzer, really, unless you're only objective is to make as heavy a projectile as possible for a given length.
Seems awfully silly for the Italians and Swedes to keep the round nosed bullets for as long as they did then, though the rounded noses were heavier rounds than the Spitzers AFAIK, so it might have been a mass issue and to help prevent overpenetration.

How long would it take to train troops on the new rifle?
As long as it took to train on the Garand IOTL, because the caliber is really not a major factor in the training of it, especially given that the US brought in 90% of it's army after the war started, so civilians just learning on a military weapon for the first time are no harder to train on either caliber.

How accurate and reliable would it be in early battles?
Within normal combat ranges more than sufficiently accurate.

Would logistics be able to keep troops sufficiently supplied with .276 ammo.
Even more so than .30-06 given that it requires less materials to make and is no more difficult to make than 7.62. Plus the POD and introduction is in the 1920s, so by the time the war starts they'd be the primary cartridge in service.
 
Instead of arguing about grams versus grains versus kilo pascals ..... How about debating how soon they could introduce a Garand firing .276 Pederson ammo?
How long would it take to train troops on the new rifle?
How accurate and reliable would it be in early battles?
Which battles?
Which enemy?
Would logistics be able to keep troops sufficiently supplied with .276 ammo.

Right, back to the OP. Thank you.

In short, it would be fielded just as fast as they fielded the .30 cal Garand in OTL. Training would be no more difficult. The only reason to possibly slow training might be initial ammunition production, but if it's adopted in 1933 the US has years to get that going and do initial training even before the big wartime ramp-up. And, it turns out that OTL they had to produce a new cartridge for the .30 cal Garand, anyway- the M2- so again no time is lost. (Almost all of the old M1903 and M1 .30-06 ammunition had to be used elsewhere as it was unsuited to the Garand.) The more interesting question will involve some follow-on changes that I have in mind, like a .276 cal BAR. That'll be more involved, and fielded much much later.

It would probably be at least as reliable and as accurate. And actually, the .30 cal grand had a lot more teething problems than most people think- essentially all related to the over-powered cartridge, except for the issues with the gas-trap system. The .276 cal grand would avoid almost all of this.

Battles and enemy are what the ATL is about.

Dual-ammunition supply has been shown by history to not be much of an issue. There will be a few SNAFUs of course, some of which I will cover, but big-picture? Not much.
 
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Deleted member 1487

Granted that sectional density is a factor in the BC equation, but you're overlooking the fact that we have already made high-BC 6mm projectiles out of lead. (Thus the existence of benchrest and other target cartridges like the 6mmPPC.) So almost certainly we can make a 5.56mm one out of copper. Perhaps not long/skinny enough to reach BCs as high as the 6mm and 6.5mm ones while remaining stable, but certainly significantly better. But my (small) doubt about that is exactly why I included 6mm as an option, there- I know it's already been done. Heck, we can keep from making it too long for stability by putting a slug of tungsten in the base to up the sectional density if we have to.
Sure, I'm not challenging that. I don't know what the longest we are making the 5.56 in now is though. By definition the 6mm would have better sectional density due to being a wider, heavier round if elongated to the max, longer and heavier than the 5.56 could possibly be and be flight stable. The problem is if you get into weird alloys you're also having to deal with cost of the round AND issue with barrel wear, as I already quoted with the high hardness rounds they had to coat in Teflon.
https://en.wikipedia.org/wiki/Teflon-coated_bullet
Besides tungsten bullets are hardly new technology, nor are copper bullets and other weird alloys, they just are EXPENSIVE, especially in the quantities demanded and would be needed in the event of a major war.
 
Probably what happened, for some reason I find it hard to follow your posts.

I will admit that I have a tendency towards verbosity and complex sentence and paragraph structure. I can't shake it, though.

It was also a total non-sequitur, so that was all my bad.

Sure, I'm not challenging that. I don't know what the longest we are making the 5.56 in now is though. By definition the 6mm would have better sectional density due to being a wider, heavier round if elongated to the max, longer and heavier than the 5.56 could possibly be and be flight stable. The problem is if you get into weird alloys you're also having to deal with cost of the round AND issue with barrel wear...[/QUOTE]

Granted. That's why I waffled. But it could be done.

... nor are copper bullets and other weird alloys, they just are EXPENSIVE, especially in the quantities demanded and would be needed in the event of a major war.

Yet the US has the copper EPR. But I guess that if there is one thing the US is god at, it's spending ridiculous amounts o money on it's military, huh? :)
 
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Deleted member 1487

Granted. That's why I waffled. But it could be done.
Sure, but it could be done better with bigger calibers. The trick is finding out which is the optimal given modern advancements in casing/weight and powders.

Anyway in terms of the idea behind this thread. .276 Pedersen is the US best! Any more ideas in getting this to happen?
 
Anyway in terms of the idea behind this thread. .276 Pedersen is the US best! Any more ideas in getting this to happen?

Something along the lines of "no useful semi-auto with full power ammo" would probably have gotten some momentum.

Also, in a previous discussion of the matter, I was thinking of the Marines being sent south in expeditions, and there was a big necessity of firepower increase along with lessening weight.
 
Sure, but it could be done better with bigger calibers.

Yes, though at a weight and recoil/controllability penalty, both of which are critical for a modern service rifle. You cannot only cite ballistic performance in this instance, or pretty soon you're proposing that every infantryman have a .50-caliber rifle!

The trick is finding out which is the optimal given modern advancements in casing/weight and powders.

Yes, what I'm saying is that with modern technology (non-lead bullets, polymer cased-telescoped casings, etc) that the "optimum tradeoff" has moved a bit and we can get better range for no appreciable recoil penalty and actually a lower weight.

But I'm done talking about modern cartridges, so...


Anyway in terms of the idea behind this thread. .276 Pedersen is the US best! Any more ideas in getting this to happen?

I have a ton of notes, and a few vignettes made. I'm actually toying with the idea of releasing the TL for anyone who wants to to write WWII vignettes when the time comes, since that's not what I'm interested in. If it works well I could do it with other wars. I mean, I could "officially" start it right now, if you really want, but I'm still getting ducks in rows. I'd also really like to know with higher confidence that the ZH-29 was as influential as it is being presented.
 
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