US adopts 6mm caliber in 1930s

[Deleted member 1487]

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

That's a big disagree from me. The .22 Spitfire/Gustafson was quite a bit superior to the .30:
https://forum.cartridgecollectors.org/t/22-carbine-experimental-cartridge/16863/2

Over the course of the next nine months the cartridge was subjected to the usual pressure, functioning, velocity, penetration, and accuracy tests. It was concluded that the carbine was capable of good performance when firing 22 caliber bullets in excess of 3000 fps. When compared with the cal 30 M2 it was found to be superior in all respects. It was recommended that five carbines and 20,000 rounds of ammunition be procured and further tested to learn if the combination offered any military advantages over what was currently employed. The cartridge was included in the SALVO I tests in 1956.

https://www.thefirearmblog.com/blog/2014/07/08/weekly-dtic-hitchman-gustafson-reports/

Even the relatively tame .22 Gustafson cartridge – firing a lightweight 41 grain bullet at 3,000 ft/s – was determined by Gustafson to present acceptable ballistics and lethality out to 400 yards, even firing on the M1 Garand qualification course of fire (it was chosen, as the Carbine course was deemed “too easy” for the high velocity modified Carbines). In fact, the .22 caliber Carbine proved superior in the course of fire to the M1 Garand, out to 300 meters. Gustafson’s final recommendation was that .45 caliber submachine guns and .30 caliber carbines could be replaced with such a high velocity weapon – which they eventually were.

And the Gustafson report itself:
https://archive.org/details/DTIC_AD0022349/page/n7

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.

Not sure that was going to make things much better. The magazine would have to be huge, which means bipod time, and an increased length and weight of the weapon (the receiver needs to be lengthened to take the BAR magazine), while automatic fire would be too much for the rifle. It would assist with reloads, but it changes the weapon quite a bit. Plus it existed IOTL, the T20, but was never procured.

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

As of 1945 due to the bomb damage Silesia and Berlin were more important than the Ruhr. By the time the Wallies took it the industry was out of commission. Silesia until late in the war was largely outside of bombing range, so had the bunch of remaining operational resources. Likely there isn't much difference in distribution between the fronts compared to OTL, especially after the Ruhr is taken.

 

[Zincwarrior]

I understand. However, per your article those experiments are in the 1950s. Thats substantially after the timeframe of the discussion, and I am considering that the focus would be on the battle rifle. .30 carbine is perfect for a rifle with pragmatic 150 - 200 yard range for noncombat infantry. AS noted in the thread about British and M2s, its really a better version of an SMG to arm guys doing everything other than firing Garands.

Not sure that was going to make things much better. The magazine would have to be huge, which means bipod time, and an increased length and weight of the weapon (the receiver needs to be lengthened to take the BAR magazine), while automatic fire would be too much for the rifle. It would assist with reloads, but it changes the weapon quite a bit. Plus it existed IOTL, the T20, but was never procured.

I think there is a misconception. I am referring to something akin to a 20 rounder magazine. It becomes an M14 / FAL style battle rifle but in the 30s. Its the same idea as the Soviet SVT 40 (also being designed at this timeframe) and later MAS 49.

Something like this:

I should be clear in my discussions on the topic. I am not saying a smaller round would be bad. I am more noting that the elements the US is putting into play: semi auto rifle and box fed utility guns, are already game changers. A different cartridge might help, but it would be evolutionary vs. revolutionary, unless you go with something select fire.

Now if we're talking an M2 carbine in a better cartridge then yowsa...

 

[Deleted member 1487]

I understand. However, per your article those experiments are in the 1950s. Thats substantially after the timeframe of the discussion, and I am considering that the focus would be on the battle rifle. .30 carbine is perfect for a rifle with pragmatic 150 - 200 yard range for noncombat infantry. AS noted in the thread about British and M2s, its really a better version of an SMG to arm guys doing everything other than firing Garands.

Those tests used nothing that wasn't available in the 1930s-40s. All I'm suggesting is the Kent report is read and heeded by US army weapons designers, so the M1 Carbine is designed around a small fast bullet to take advantage of the effects noted in that report. The advantages are lessened recoil, lower weight per cartridge, cheaper bullets (less than half the weight), and overall being easier to use for a non-combat person, while remaining more effective than the M1 Garand out to 300 yards. It extends the range of the weapon while increasing it's overall performance and being cheaper. You're right, as noted by Gustafson it would replace all SMGs and .30 carbine weapons as well as most pistols and honestly, though not claimed in the report directly, would replace the M1 Garand in some instances.

I think there is a misconception. I am referring to something akin to a 20 rounder magazine. It becomes an M14 / FAL style battle rifle but in the 30s. Its the same idea as the Soviet SVT 40 (also being designed at this timeframe) and later MAS 49.

Something like this:

I should be clear in my discussions on the topic. I am not saying a smaller round would be bad. I am more noting that the elements the US is putting into play: semi auto rifle and box fed utility guns, are already game changers. A different cartridge might help, but it would be evolutionary vs. revolutionary, unless you go with something select fire.

Now if we're talking an M2 carbine in a better cartridge then yowsa...

Considering the T20 wasn't available until 1945 you'd need a very different POD than what we've been talking about in this thread to get that in the 1930s. They were fully occupied trying to get the gas trap Garand to work until 1940. The SVT-40 ended up considerably worse than the Garand BTW...

And yes I've moved on to the idea of the M1/2 Carbine being SCHV because of the report in OP, as it seems the funding wasn't there for a caliber shift given the personalities involved in the 1930s.

 

[Zincwarrior]

And yes I've moved on to the idea of the M1/2 Carbine being SCHV because of the report in OP, as it seems the funding wasn't there for a caliber shift given the personalities involved in the 1930s.

I am not sure of what "SCHV" means here. If you are arguing for a smaller caliber M2 carbine with longer reach, that could have been very good. It would not have been a game changer, but it could have been very good, if well developed.

Considering the T20 wasn't available until 1945 you'd need a very different POD than what we've been talking about in this thread to get that in the 1930s. They were fully occupied trying to get the gas trap Garand to work until 1940. The SVT-40 ended up considerably worse than the Garand BTW...

Agreed. They were pushing to get the Garand as it was into service, which was a very good rifle.

 

[Deleted member 1487]

I am not sure of what "SCHV" means here. If you are arguing for a smaller caliber M2 carbine with longer reach, that could have been very good. It would not have been a game changer, but it could have been very good, if well developed.

Small caliber, high velocity. I'm arguing for the same carbine rifle, but with a .22 caliber cartridge; IOTL the existing cartridge and rifle were able to use the .22 modified version just by necking down the cartridge and changing the barrel, otherwise the rifle and cartridge were exactly the same. Powder load was higher though. That resulted in a longer reach carbine, flatter trajectory, better wounded power, and less recoil. It would have dominated within 300m, which is the max range where infantry fired their rifles in WW2 and Korea despite the Garand having much higher range.

Agreed. They were pushing to get the Garand as it was into service, which was a very good rifle.

With the limitations it had, sure it was the best battle rifle of the time period.

 

[Zincwarrior]

Small caliber, high velocity. I'm arguing for the same carbine rifle, but with a .22 caliber cartridge; IOTL the existing cartridge and rifle were able to use the .22 modified version just by necking down the cartridge and changing the barrel, otherwise the rifle and cartridge were exactly the same. Powder load was higher though. That resulted in a longer reach carbine, flatter trajectory, better wounded power, and less recoil. It would have dominated within 300m, which is the max range where infantry fired their rifles in WW2 and Korea despite the Garand having much higher range.

Gotcha. Thank you for the clarification. So really you're developing an assault rifle with wooden furniture (not a necked down big rifle round but a reduced caliber rifle round). Yes that would be advantageous against KAR-98 equipped troops.

Retool BARs for the caliber with QC barrels and you're looking at infantry more in common with Vietnam GIs. Very impressive. EDIT: Now we just need Colonel Kurtz on the beach shouting "Charlie don't surf!"

 

[marathag]

IIRC but there were thoughts about doing that.

That's where Garand started, but Army didn't want protruding magazines,

so that's why the Garand got the en-bloc and the Johnson the rotary

EDIt Hmm, photo not embedding properly http://nps.gov/spar/learn/historyculture/images/CASE_35.jpg

 

[Deleted member 1487]

Gotcha. Thank you for the clarification. So really you're developing an assault rifle with wooden furniture (not a necked down big rifle round but a reduced caliber rifle round). Yes that would be advantageous against KAR-98 equipped troops.

The M2 Carbine basically was an underpowered assault rifle by accident, with a small caliber high velocity cartridge it would be clearly an assault rifle and even superior to a SMG/semi-auto rifle team, as the STG44 was found to be superior to the Garand in combat effectiveness.

Since this .22 Carbine would replace SMGs as well as pistols and other carbines it also simplified logistics and increases combat power substantially, while allowing them to carry even more ammo. For instance the entire .22 Gustafson cartridge, case/powder/bullet, was about 11.5 grams. Just the bullet of the .45 ACP ammo was 15 grams! .30 Carbine cartridge weight was 12.6 grams in total. M2 Ball in .30-06 was 27 grams. So you could nearly have 2.5x as much ammo for the same weight, not counting extra that could be carried due to the lighter carbine weight vs. the Garand. IIRC the 7.92 Mauser was even heavier than the .30-06 due to the weight of the bullet. So having something like this would be a major advantage over any sort of rifle equipped soldier, even with a select fire battle rifle.

Retool BARs for the caliber with QC barrels and you're looking at infantry more in common with Vietnam GIs. Very impressive. EDIT: Now we just need Colonel Kurtz on the beach shouting "Charlie don't surf!"

Or just use the Johnson LMG.

 

[WaterproofPotatoes]

Or just use the Johnson LMG.

Would this Johnny Gun be firing the improved .22, the improved 6 mm or some flavour of 7.62 mm?

 

[Deleted member 1487]

Would this Johnny Gun be firing the improved .22, the improved 6 mm or some flavour of 7.62 mm?

Even the OTL Johnson would be superior to the BAR.
But if you want the best version of it I'd say the 6mm round proposed in the OP, which means it could be lighter and use a double stack 30 round magazine. It wouldn't be perfect, but it would be probably the best non-belt fed LMG of the era and for years to come.

 

[yulzari]

Trivial pint but a slimmer case would allow a 10 round en bloc Mannlicher clip in the M1 Garand. To get period demanded performance in the same overall length that means a lighter bullet and a smaller diameter is a simple way to do this without a bullet that is too short for the speed/calibre. Thus you get close to a 8mm round by a different route than starting with the calibre. A clear improvement in ammunition capacity over the OTL M1 Garand. Then someone will notice that a heavier (quick change?) barrel and bipod allows the BAR to be replaced too with the same ammunition. Stretching the rubber band further, could a short barelled folding stock version fill the M1 Carbine role? Lots of muzzle flash and blast and heavier but short enough for a PDW for the non infantry that will still work if they have to actually play soldiers for real. The Browning MMG would stay in .30-06 for it's proper MMG role.

 

[WaterproofPotatoes]

Even the OTL Johnson would be superior to the BAR.
But if you want the best version of it I'd say the 6mm round proposed in the OP, which means it could be lighter and use a double stack 30 round magazine. It wouldn't be perfect, but it would be probably the best non-belt fed LMG of the era and for years to come.

That makes good sense!

Perhaps drawing on too much hindsight, but the 6mm Johnny Gun would allow the rifle squad to push its range out farther. Because the .22 carbine-armed troops can carry 2.5x the ammo and are more confident firing, they aren't just glorified ammo carriers for the LMG, and the fact that their ammo can't be fed into the LMG becomes less important too.

Also hindsight, but there really isn't any way to get a perfect universal cartridge that can replace all current SMG, carbine, battle rifle, and LMG rounds and do equally well in each role.

 

[Deleted member 1487]

That makes good sense!

Perhaps drawing on too much hindsight, but the 6mm Johnny Gun would allow the rifle squad to push its range out farther. Because the .22 carbine-armed troops can carry 2.5x the ammo and are more confident firing, they aren't just glorified ammo carriers for the LMG, and the fact that their ammo can't be fed into the LMG becomes less important too.

Also hindsight, but there really isn't any way to get a perfect universal cartridge that can replace all current SMG, carbine, battle rifle, and LMG rounds and do equally well in each role.

A Jack of all Trades is master of none. The long range 6mm is probably the closest one can get to a 'universal' cartridge for infantry that will perform at least decently in all direct fire roles, but in specific roles it will be bested by specialized rounds.

 

[Deleted member 1487]

Trivial pint but a slimmer case would allow a 10 round en bloc Mannlicher clip in the M1 Garand. To get period demanded performance in the same overall length that means a lighter bullet and a smaller diameter is a simple way to do this without a bullet that is too short for the speed/calibre. Thus you get close to a 8mm round by a different route than starting with the calibre. A clear improvement in ammunition capacity over the OTL M1 Garand. Then someone will notice that a heavier (quick change?) barrel and bipod allows the BAR to be replaced too with the same ammunition. Stretching the rubber band further, could a short barelled folding stock version fill the M1 Carbine role? Lots of muzzle flash and blast and heavier but short enough for a PDW for the non infantry that will still work if they have to actually play soldiers for real. The Browning MMG would stay in .30-06 for it's proper MMG role.

Honestly I think an 18 inch barrel like the M1 Carbine wouldn't result in a heavy blast especially with a flash hider muzzle device. The quality of the folding stock would matter a lot and there is no way that the OTL M1 Carbine could handle such a 6mm round, it would have to be a lightened Garand with shorter barrel and folding stock like the Tanker Carbine.

I think though that TTL's Garand in 6mm with a box mag and select fire would be able to have a heavy barrel and function as an RPK style SAW, especially if there were 2-3 per squad. Then you have scales of economy in production, plus commonality in use, and don't need a magazine fed LMG and still have an exceptionally light, for the period, automatic weapon.

Thermal buildup will be an issue though, so probably after 2-3 magazines they will have to lock open the bolt and let it 'air out' for 90 seconds. If you have 3 per squad then you could alternate the base of fire so that that isn't such an issue. Have 2 of them firing and when they take a brake to cool off then the 3rd operates. IIRC that is sort of how the BAR operated, though it could go longer between rest periods.

 

[TonyA]

Trivial pint but a slimmer case would allow a 10 round en bloc Mannlicher clip in the M1 Garand. To get period demanded performance in the same overall length that means a lighter bullet and a smaller diameter is a simple way to do this without a bullet that is too short for the speed/calibre. Thus you get close to a 8mm round by a different route than starting with the calibre. A clear improvement in ammunition capacity over the OTL M1 Garand. Then someone will notice that a heavier (quick change?) barrel and bipod allows the BAR to be replaced too with the same ammunition. Stretching the rubber band further, could a short barelled folding stock version fill the M1 Carbine role? Lots of muzzle flash and blast and heavier but short enough for a PDW for the non infantry that will still work if they have to actually play soldiers for real. The Browning MMG would stay in .30-06 for it's proper MMG role.

Yeah! Getting the average Joe or the average general to buy into a .22 caliber man killer military weapon is quite a stretch for the period, but, what you're proposing is the sort of thing that might actually get some traction with the establishment of the day. Incrementalism gets crucified most of the time, but, it frequently gets done, and there's always the "perfect vs good enough" argument.

 

[SsgtC]

Thermal buildup will be an issue though, so probably after 2-3 magazines they will have to lock open the bolt and let it 'air out' for 90 seconds. If you have 3 per squad then you could alternate the base of fire so that that isn't such an issue. Have 2 of them firing and when they take a brake to cool off then the 3rd operates. IIRC that is sort of how the BAR operated, though it could go longer between rest periods.

One thing in the BARs favor was that the smaller 15 round magazines meant that there were more "breaks" while firing, slowing the build up of heat. It was an unintentional benefit, but it was still there

 

[Deleted member 1487]

One thing in the BARs favor was that the smaller 15 round magazines meant that there were more "breaks" while firing, slowing the build up of heat. It was an unintentional benefit, but it was still there

They had 20 round mags and 40 round AA mags, which then reduced practical rate of fire.
https://en.wikipedia.org/wiki/M1918_Browning_Automatic_Rifle

 

[Blue cat]

That's where Garand started, but Army didn't want protruding magazines,

so that's why the Garand got the en-bloc and the Johnson the rotary

EDIt Hmm, photo not embedding properly http://nps.gov/spar/learn/historyculture/images/CASE_35.jpg

With hindsight I wonder why the initial solution for the Garand wasn't a shorter box magazine that didn't protrude that could also be topped up with stripper clips without being removed from the firearm ?

 

[SsgtC]

With hindsight I wonder why the initial solution for the Garand wasn't a shorter box magazine that didn't protrude that could also be topped up with stripper clips without being removed from the firearm ?

Complexity, probably. Basic rule of thumb for infantry weapons is that you want them as idiot proof as possible. Because Private McDumbfuck will find a way to fuck up even the simplest tasks. So the easier you can make things, the lower the chance for massive fuck up. For example, I've seen more idiots than I can count actually manage to jam an entire stripper clip into an M-16 magazine while loading it because that's what they thought they were supposed to do. I can only imagine how many times privates in the field would fuck up loading under combat conditions.

 

[Blue cat]

Complexity, probably. Basic rule of thumb for infantry weapons is that you want them as idiot proof as possible. Because Private McDumbfuck will find a way to fuck up even the simplest tasks. So the easier you can make things, the lower the chance for massive fuck up. For example, I've seen more idiots than I can count actually manage to jam an entire stripper clip into an M-16 magazine while loading it because that's what they thought they were supposed to do. I can only imagine how many times privates in the field would fuck up loading under combat conditions.

That does make sense, although a number of fire arms have been fielded with magazines that can be refilled / topped up with stripper clips while still attached to the fire arm.

But yes I can see your point.