US adopts 6mm caliber in 1930s

[SsgtC]

Wonder how the .276 Pedersen even got that far. They were ready to adopt it until at the last minute Doug sprung that argument...what gives?

Budgets. Dugout Doug was Chief of Staff of the Army. Someone probably showed him the cost to replace all those rounds. Or how much those rounds had cost to produce and he didn't want Congress coming down on him screaming about how wasteful the Army is and restricting his funding even more than it already was in peace time

 

[MichaelWest]

Not the .276 Garand, just a .243 Garand. The 7mm Pedersen was too powerful to make it an M1 Carbine replacement, the 6mm version would be light enough to do both roles though.


I suppose if they adopt either the .276 Garand or keep the .30 version then they might opt for a SCHV Carbine assuming that they still heed the report from OP. Then we might see a .20 caliber M1 Carbine, later on in the war with select fire and a 30 round magazine. That would be a true assault rifle.
In fact something very similar to what a .20 caliber + .351 WSL rimless case cartridge would be exists now:
https://en.wikipedia.org/wiki/.20_VarTarg
Granted though it's performance relies on high energy modern powders to get to 1000mps at the muzzle, so not necessarily practical in WW2 from that sized case and uses a 24 inch barrel, but it shows what could be possible. By all accounts even the most powerful .20 caliber cartridges with 1200mps muzzle velocity are very low recoil and aren't hard on the barrel of a rifle, so would make for a very controllable automatic weapon cartridge.


Not even just that, but the FN BAR modifications:
https://en.wikipedia.org/wiki/M1918_Browning_Automatic_Rifle#Belgium
QC barrel, simplified construction and takedown, and better rate reduction mechanism. That's not even counting the belt feed options a few people developed for the weapon. Forget the competition to the BAR even, just the modernization efforts for the BAR could have made it a cheaper, easier to make weapon, that worked better than the base version. Really kind of odd considering even the Soviets were able to develop a swap-able belt feed mechanism for the DP-28.

I like the M1 Carbine, I think its reputation is below where it should be, so I hope we keep it. I find the .276 fascinating for its potential. To me it looks like the "intermediate" round we want, something we did not see until a generation later. It should spark a revisit to the LMG, in my opinion the BAR was ideal partner to the M1903 in its era, a superlative weapon before the Garand, but with the Garand it is no longer quite right, not really a MG, it is now a weapon looking for a mission. Of course without a good LMG the BAR is what is on hand. Might we see the "automatic rifle" also base of fire dust sprinkled on the Garand as it was the M14 to cobble up a SAW version in .276? Heavier barrel, magazine fed, bipod, lighter than BAR, common ammo with Grand, or do we see full auto as an option to bump the Squad up in volume of fire?

 

[Deleted member 1487]

Budgets. Dugout Doug was Chief of Staff of the Army. Someone probably showed him the cost to replace all those rounds. Or how much those rounds had cost to produce and he didn't want Congress coming down on him screaming about how wasteful the Army is and restricting his funding even more than it already was in peace time

AFAIK the money was already allocated for not just the new rifles but also the cartridges for them. Though the production lines already existed for the .30-06 which made making the M2 Ball cartridges less expensive than setting up production of a new caliber cartridge, it couldn't have been that much considering how much smaller the cartridges were.
Do you per chance have a history of the development of the rifle/cartridge that documents Doug's decision?

I, for one, am glad that .276 Pedersen didn't go anywhere. It may be a theoretically more appropriate for an infantry rifle, but the case taper and lubrication problem are only the most immediate issues. Because .276 Pedersen was ballistically similar to .280 British, it would fair similarly poorly in anything larger than an LMG, but it would still be considered too big by modern standards informed by the success of SCHV. I also don't want to see a BAR with an AK mag.

Why would the taper be an issue? It was hardly excessive. The lubrication problem was unlikely to be an issue given that lacquered steel cases were used throughout the war by all sides and didn't have significant issues until the quality of the lacquer fell in the defeated toward the end of the war.
AFAIK the .276 Pedersen was only intended for the BAR and rifle not MMG/HMGs, so it was a non-issue there unlike the .280 British, which would have been for everything, something that fatally compromised that cartridge. In terms of ballistics the .276 Pedersen was superior to the .280 British at any range due to having a boat tail and IIRC having a higher muzzle velocity, but that might depend on which version of the .280 British (final higher powered version competing with the 7.62x51 vs. the early lower powered assault rifle concept version) we're talking about and which bullet they used for the Pedersen (IIRC there was a 130 grain and 140 grain).

I like the M1 Carbine, I think its reputation is below where it should be, so I hope we keep it. I find the .276 fascinating for its potential. To me it looks like the "intermediate" round we want, something we did not see until a generation later. It should spark a revisit to the LMG, in my opinion the BAR was ideal partner to the M1903 in its era, a superlative weapon before the Garand, but with the Garand it is no longer quite right, not really a MG, it is now a weapon looking for a mission. Of course without a good LMG the BAR is what is on hand. Might we see the "automatic rifle" also base of fire dust sprinkled on the Garand as it was the M14 to cobble up a SAW version in .276? Heavier barrel, magazine fed, bipod, lighter than BAR, common ammo with Grand, or do we see full auto as an option to bump the Squad up in volume of fire?

The M1 Carbine as a rifle I agree, but the .30 Carbine cartridge I don't. I think a slightly longer version with a 40 grain .20 caliber bullet would have been far superior due to the potential speed and resulting flat trajectory and wounding/killing power it would have.

The .276 Pedersen was a bit too powerful to be an intermediate cartridge, it was certainly quite a bit less powerful than the .30-06, but around the power of the late overpowered .280 British cartridge, which was in the battle rifle power range, significantly above that of the 7.62x39.

Don't forget about the Johnson LMG, which was a lighter, cheaper BAR with all the modern design elements including an in line stock to prevent muzzle rise and help mitigate recoil. With a lighter cartridge than the .30-06, even the .276 Pedersen, it would have been even better than it was IOTL. In fact with the BAR being too much gun for even the Pedersen round perhaps the Johnson LMG would get the chance it deserved to prove itself as a viable SAW...with a bit of improvement that would undoubtedly come with combat experience. In fact with a lighter cartridge in service for it to be designed around it would probably be even lighter and easier/cheaper to make.

I'm not sure they'd develop a 'heavy' Garand during WW2, as the select fire version took FOREVER to appear and required a box magazine. That said there would be no need for an M14 given that the conversion to the 7.62x51 NATO probably wouldn't happen ITTL and they could just adopt a conversion of the Garand to select fire with a box mag like the Italians did with the BM-59. Post-war we'd probably see the T20 experimental rifle though by the end of WW2 and in time for Korea. Then you'd see the HBAR version, as they built one of the T20 rifle before starting what became the M14 project. With the lower powder load and therefore heat build up it might be relatively viable, perhaps no worse than the non-QC barrel BAR in terms of heat build up, but worse than the Soviet RPK and RPD.

 

[SsgtC]

AFAIK the money was already allocated for not just the new rifles but also the cartridges for them. Though the production lines already existed for the .30-06 which made making the M2 Ball cartridges less expensive than setting up production of a new caliber cartridge, it couldn't have been that much considering how much smaller the cartridges were.
Do you per chance have a history of the development of the rifle/cartridge that documents Doug's decision?

Not at hand. I'm moving to a new house so all my books are packed at the moment. But going off memory, his reasoning was that the Army could save money by ordering the Garand in .30-06 by using the preexisting stocks of munitions. I believe the thinking was that the money for the new cartridge could be better used for other modernization programs

 

[marathag]

I, for one, am glad that .276 Pedersen didn't go anywhere. It may be a theoretically more appropriate for an infantry rifle, but the case taper and lubrication problem are only the most immediate issues

Lube was only for the Pederson Rifle, that lost to Garand in the trials

Or how much those rounds had cost to produce

Then why did they want to spend money on new semiauto rifles? Millions of Enfields and Springfields left over from the Great War, and those rifles could use that ammo.

 

[Deleted member 1487]

Not at hand. I'm moving to a new house so all my books are packed at the moment. But going off memory, his reasoning was that the Army could save money by ordering the Garand in .30-06 by using the preexisting stocks of munitions. I believe the thinking was that the money for the new cartridge could be better used for other modernization programs

I've seen that repeated a fair bit, but haven't seen any books about the history of how all that went down, just references to Hatcher's notebook and an unsourced article from the American Rifleman. If you can recommend any books I'd be interested.
Likely though the budget was a pretty significant problem by 1932, so it would seem the change would need to come before then when Doug weighed in.

 

[Not James Stockdale]

Why would the taper be an issue? It was hardly excessive.

The .276 Pedersen had significantly more case taper than the 7.62 x 39 cartridge. The base to shoulder ratio was 1.16 vs 1.13. For comparison, 5.56 NATO is 1.06 and 7.62 NATO is 1.03. The .276 T2 cartridge that would have been adopted (not the trials cartridge) used the same case head as the .30-06 so the .276 Garand wouldn't have had the 10 round magazine.

 

[Deleted member 1487]

The .276 Pedersen had significantly more case taper than the 7.62 x 39 cartridge. The base to shoulder ratio was 1.16 vs 1.13. For comparison, 5.56 NATO is 1.06 and 7.62 NATO is 1.03. The .276 T2 cartridge that would have been adopted (not the trials cartridge) used the same case head as the .30-06 so the .276 Garand wouldn't have had the 10 round magazine.

Ok then I'm thinking of a different cartridge. I could see why they tried to standardize, but what is the big deal about having a sharper shoulder? Seems to work just fine with the 5.45x39.

 

[SsgtC]

Then why did they want to spend money on new semiauto rifles? Millions of Enfields and Springfields left over from the Great War, and those rifles could use that ammo.

Semi-auto was seen as a massive improvement in firepower without the added cost and complexity of adding machine guns to every squad

 

[SsgtC]

I've seen that repeated a fair bit, but haven't seen any books about the history of how all that went down, just references to Hatcher's notebook and an unsourced article from the American Rifleman. If you can recommend any books I'd be interested.
Likely though the budget was a pretty significant problem by 1932, so it would seem the change would need to come before then when Doug weighed in.

Once I dig them out I'll let you know. It's been awhile since I've read them

 

[Deleted member 1487]

Semi-auto was seen as a massive improvement in firepower without the added cost and complexity of adding machine guns to every squad

An single MG per squad is cheaper than replacing the entire rifle stocks, which is why the Germans pursued the MG34 instead of the semi-auto rifle program they were looking at.
Since it would replace the BAR and M1919 while increasing firepower of a squad/platoon a belt fed MG like the T10 would have probably saved them money especially if they didn't change the cartridge or even need to adopt the M2 ball ammo. Seems more like the US Army fetishized the idea of the marksman saving them ammo and putting out long range accurate fire better than an MG.

 

[SsgtC]

An single MG per squad is cheaper than replacing the entire rifle stocks, which is why the Germans pursued the MG34 instead of the semi-auto rifle program they were looking at.
Since it would replace the BAR and M1919 while increasing firepower of a squad/platoon a belt fed MG like the T10 would have probably saved them money especially if they didn't change the cartridge or even need to adopt the M2 ball ammo. Seems more like the US Army fetishized the idea of the marksman saving them ammo and putting out long range accurate fire better than an MG.

I didn't say it made sense. Lol.

 

[Deleted member 1487]

I didn't say it made sense. Lol.

Right, I should know that about US smalls arms procurement in the 20th century by now.

 

[Deleted member 1487]

I suppose now I should ask about a .22 Spitfire M1 Carbine if the funding issue precludes a 6 or 7mm rifle/autorifle cartridge.
Since the study in OP did talk about something in that caliber range being ideal for out to 500 yards, I wonder if they might not try and make a fast .22 round using the .351 WSL rimless, as the resulting round would be lighter and cheaper than the .30 Carbine, while using existing .22 barrel making equipment, which was plentiful thanks to .22lr being widespread. Even without the larger capacity magazine or select fire that would be one heck of a rifle/cartridge for WW2, as it's range would be at least 400 yards, very flat firing, and more lethal than the .30 Carbine.

 

[Crowbar Six]

There have been several examples of .276 ammo working perfectly after 80 odd years later with no issues.

 

[marathag]

There have been several examples of .276 ammo working perfectly after 80 odd years later with no issues.

firing old surplus ammo from the '20s, most of it does work, with a few duds and underperforming MVs. Before the '20s, it spotty. Before WWI, it's bad, with smokeless powders and primers both deteriorating. further back, Black Powder is almost always as good as the day it was made, but Mercury based primers are really poor in longevity

 

[WaterproofPotatoes]

AFAIK the .276 Pedersen was only intended for the BAR and rifle not MMG/HMGs, so it was a non-issue there unlike the .280 British, which would have been for everything, something that fatally compromised that cartridge. In terms of ballistics the .276 Pedersen was superior to the .280 British at any range due to having a boat tail and IIRC having a higher muzzle velocity, but that might depend on which version of the .280 British (final higher powered version competing with the 7.62x51 vs. the early lower powered assault rifle concept version) we're talking about and which bullet they used for the Pedersen (IIRC there was a 130 grain and 140 grain

I remember doing some reading about it a while back, and there were several different flavours of .280 British. It was designed to be better for long range shooting than .270 British (7×46mm) which made use of a high muzzle velocity and a light bullet, and was quite controllable but wasn't great beyond IIRC 400m which would have been an issue in machine guns.

.280 and .280 Optimum (7×43mm), although they kicked about 2/3 as hard as .303, still reliably penetrated wood and metal at long ranges on a range better than either .303 or 30-06, but couldn't punch through as much wood and sheet metal at 10 yards as the elephant guns could, thus leading to the US declaring it unacceptable.

.280 High Velocity (7×50mm) and .280 Second Optimum (7×49mm) were good all around, but there was no market for them. FN actually sold Venezuela 5000 FALs in .280 2nd Optimum in the mid-50s but these were rechambered for 7.62 NATO in the 60s

.280/30 and T65 (.280x51mm) were more powerful still and virtually uncontrollable in full auto, essentially replicating 7.62×51mm NATO

 

[Dave Shoup]

yes switching cartridges and caliber has a host of add on costs like: building/converting a production line to provide the ammo, making new tools for barrels, that adds cost to an already expensive program that is fighting with the rest of us rearmament for money

It's worth pointing out that in 1932, when the .276 was set aside, the US was acquiring its first generation of all metal monoplane pursuit, attack, and bombardment aircraft, and funding R&D toward what were - at the time - absolutely futuristic ideas like Project A and Project 88... small arms ammunition procurement wasn't quite in the same league.

 

[James Ricker]

So Wallies take Berlin and all the people that died in the last 30 days of the war due to Nazi atrocities are spared?

The Soviets still take Berlin because losses on the Western Front will be replaced from troops with the Eastern Front. Because the Rhur valley is a lot more vital to the German war effort than East Prussia

 

[Zincwarrior]

AFAIK the money was already allocated for not just the new rifles but also the cartridges for them. Though the production lines already existed for the .30-06 which made making the M2 Ball cartridges less expensive than setting up production of a new caliber cartridge, it couldn't have been that much considering how much smaller the cartridges were.
Do you per chance have a history of the development of the rifle/cartridge that documents Doug's decision?


Why would the taper be an issue? It was hardly excessive. The lubrication problem was unlikely to be an issue given that lacquered steel cases were used throughout the war by all sides and didn't have significant issues until the quality of the lacquer fell in the defeated toward the end of the war.
AFAIK the .276 Pedersen was only intended for the BAR and rifle not MMG/HMGs, so it was a non-issue there unlike the .280 British, which would have been for everything, something that fatally compromised that cartridge. In terms of ballistics the .276 Pedersen was superior to the .280 British at any range due to having a boat tail and IIRC having a higher muzzle velocity, but that might depend on which version of the .280 British (final higher powered version competing with the 7.62x51 vs. the early lower powered assault rifle concept version) we're talking about and which bullet they used for the Pedersen (IIRC there was a 130 grain and 140 grain).


The M1 Carbine as a rifle I agree, but the .30 Carbine cartridge I don't. I think a slightly longer version with a 40 grain .20 caliber bullet would have been far superior due to the potential speed and resulting flat trajectory and wounding/killing power it would have.

The .276 Pedersen was a bit too powerful to be an intermediate cartridge, it was certainly quite a bit less powerful than the .30-06, but around the power of the late overpowered .280 British cartridge, which was in the battle rifle power range, significantly above that of the 7.62x39.

Don't forget about the Johnson LMG, which was a lighter, cheaper BAR with all the modern design elements including an in line stock to prevent muzzle rise and help mitigate recoil. With a lighter cartridge than the .30-06, even the .276 Pedersen, it would have been even better than it was IOTL. In fact with the BAR being too much gun for even the Pedersen round perhaps the Johnson LMG would get the chance it deserved to prove itself as a viable SAW...with a bit of improvement that would undoubtedly come with combat experience. In fact with a lighter cartridge in service for it to be designed around it would probably be even lighter and easier/cheaper to make.

I'm not sure they'd develop a 'heavy' Garand during WW2, as the select fire version took FOREVER to appear and required a box magazine. That said there would be no need for an M14 given that the conversion to the 7.62x51 NATO probably wouldn't happen ITTL and they could just adopt a conversion of the Garand to select fire with a box mag like the Italians did with the BM-59. Post-war we'd probably see the T20 experimental rifle though by the end of WW2 and in time for Korea. Then you'd see the HBAR version, as they built one of the T20 rifle before starting what became the M14 project. With the lower powder load and therefore heat build up it might be relatively viable, perhaps no worse than the non-QC barrel BAR in terms of heat build up, but worse than the Soviet RPK and RPD.

The .30 carbine round is perfect for what it was intended. No need to change it.

Frankly if we're changing anything on the fly it should be modifying the Garand to take a well designed box magazine. IIRC but there were thoughts about doing that. That puts a full battle rifle into the hands of the average trooper and leap frogs them into the top tier of armed infantry.