American small arms cartridges during WWII; why so little change?

[Ivanhoe]

The Navy fielded a wide variety of new small craft, boats, and ships, plus a whole slew of aircraft.

The USAAF fielded a whole bunch of new aircraft, so many models I can't keep all them straight in my head.

But why so little change in small arms cartridges?

.45 ACP, .30 Government (M1906, of course), .50 BMG, 20x110, 40mm Bofors, pretty much all in place before 1939. The US certainly had the industrial might to develop new cartridges, but TMK did not do so.

I can imagine one argument being that existing cartridges were good enough, but same could be said for other weapon systems. Same with the logistics train; if anyone could switch their log channels from one cartridge to another, it was the US. Factory to front in a few weeks, apparently.

 

[RichTO90]

41 minutes ago, Ivanhoe said:

The Navy fielded a wide variety of new small craft, boats, and ships, plus a whole slew of aircraft.

The USAAF fielded a whole bunch of new aircraft, so many models I can't keep all them straight in my head.

But why so little change in small arms cartridges?

.45 ACP, .30 Government (M1906, of course), .50 BMG, 20x110, 40mm Bofors, pretty much all in place before 1939. The US certainly had the industrial might to develop new cartridges, but TMK did not do so.

I can imagine one argument being that existing cartridges were good enough, but same could be said for other weapon systems. Same with the logistics train; if anyone could switch their log channels from one cartridge to another, it was the US. Factory to front in a few weeks, apparently.

 

How many other nations besides Japan changed their pistol and rifle caliber standard before the war?

No, the 20mm and 40mm rounds in the US were both wartime developments. 20mm was adopted in 1941 from the British. Ditto 40mm, but from the Swedes via the Netherlands.

Who or what is "TMK"?

[sunday]

2 hours ago, Ivanhoe said:

The Navy fielded a wide variety of new small craft, boats, and ships, plus a whole slew of aircraft.

The USAAF fielded a whole bunch of new aircraft, so many models I can't keep all them straight in my head.

But why so little change in small arms cartridges?

.45 ACP, .30 Government (M1906, of course), .50 BMG, 20x110, 40mm Bofors, pretty much all in place before 1939. The US certainly had the industrial might to develop new cartridges, but TMK did not do so.

I can imagine one argument being that existing cartridges were good enough, but same could be said for other weapon systems. Same with the logistics train; if anyone could switch their log channels from one cartridge to another, it was the US. Factory to front in a few weeks, apparently.

 

You seem to forget .30 Carbine -  that was an innovation.

[Ivanhoe]

3 hours ago, RichTO90 said:

How many other nations besides Japan changed their pistol and rifle caliber standard before the war?

No, the 20mm and 40mm rounds in the US were both wartime developments. 20mm was adopted in 1941 from the British. Ditto 40mm, but from the Swedes via the Netherlands.

Who or what is "TMK"?

To My Knowledge

[RichTO90]

58 minutes ago, Ivanhoe said:

To My Knowledge

Thanks! 😁 I was hoping to be done with acronyms after retirement.

[rmgill]

There will always be more TLAs. 
 

Also, such large changes need a good reason. 30.06 did well. 

[Markus Becker]

14 hours ago, Ivanhoe said:

The Navy fielded a wide variety of new small craft, boats, and ships, plus a whole slew of aircraft.

The USAAF fielded a whole bunch of new aircraft, so many models I can't keep all them straight in my head.

But why so little change in small arms cartridges?

.45 ACP, .30 Government (M1906, of course), .50 BMG, 20x110, 40mm Bofors, pretty much all in place before 1939. The US certainly had the industrial might to develop new cartridges, but TMK did not do so.

I can imagine one argument being that existing cartridges were good enough, but same could be said for other weapon systems. Same with the logistics train; if anyone could switch their log channels from one cartridge to another, it was the US. Factory to front in a few weeks, apparently.

 

 

The Golden Rule of mobilisation is to mass produce what's already in production. Unless the stuff is utttlery obsolete and small arms cartridges weren't.

.45 ACP and .30-06 weren't ideal but not bad either and the US had a ton of small arms in theses calibers that were left over from WW1. Hence the M1's caliber change from .270 to the older .30-06.

The only thing that IMO could have happned was the introduction of 9mm. Handguns weren't important and the US had practically no SMG by mid 1940. At that point a Thompson M1 in 9mm would have been doable.

[seahawk]

For what?

They had a good working semi-auto rifle that shared ammo with the older bolt action rifle

the SMGs were also good

the pistol was good

the .50 was something all other nations would have loved

the .30 Browning was okayish

[Markus Becker]

1 hour ago, seahawk said:

For what?

They had a good working semi-auto rifle that shared ammo with the older bolt action rifle

the SMGs were also good

the pistol was good

the .50 was something all other nations would have loved

the .30 Browning was okayish

They didn't have the M1 until early to mid 1942. They had a few M1928 and that gun was unsuited for war because of its complexity. 

[seahawk]

M1928 was not better worse worse than many SMGs from pre-war production.

[bojan]

Yes and no. It's reliability in dirty conditions was very poor, especially if dirt got into Blish lock. Compare that to quite reliable EMP-35 or ZK-383 or Beretta.  Ergonomics left a lot to be desired and it was really heavy. IMO, it is probably worst of the pre-war SMGs, through that has to do with a fact that it was one of the first. I would even dare to call it worse than MP-18, despite that crap snail drum mag, because MP-18 was actually pretty streamlined production wise - it needed a lot of lathe work, but relatively little milling, which was most problematic one at the time. Compared to that Thompson was all milled.

OTOH, on the local SMG shooting tests M1A1 Thompson performed better than much worshiped MP-40, even through MP-40 was better SMG in practice 

 

 

Edited June 23 by bojan

[Markus Becker]

2 hours ago, seahawk said:

M1928 was not better worse worse than many SMGs from pre-war production.

By 1939 the majority of the guns made by Colt in the early 20s were still not sold. How many MP 28 had been made and sold in the meantime? 

The M1928 was a failure that was a commercial success at the last second because nobody in the USA designed something better. 

[seahawk]

Yes, but it was good enough at the time. And M1 / M1A1 were okayish, especially as the general need for SMGs was lower due to the standard rifle being a semi-auto. And the carbines also being introduced.

I really do not see the US SMGs as so bad, that it would warrant introducing a new ammo round. A better .45 SMGs could have been made, but the carbines were actually better.

[Interlinked]

It's really hard to say that they were "good enough at the time", usually that phrase is reserved for things like the Sten where it's a lot more understandable, and like the U.S with their Thompsons, the British gave section commanders Stens, not the regular riflemen.

[Markus Becker]

The M1 was supposed to be an interim gun. At 50 $ a piece it took still too much effort given the numbers needed. It was supposed to be replaced by the M2 but that was so much delayed that the M2 was skipped over in favor of the M3. 

WRT ammo, by the actual time the US military became sufficiently interested in SMG they seem to have been in the war already. So too late.

But the process could have started sooner. Mid 1940 when their mobilization began. It should have been obvious that more SMG were needed and that the M1928 would not be the weapon of choice. 

Though the most realistic alternative would be the British. They and the French started ordering as November 1939. Given the insane price, WI they had taken a M1928 to Savage Arms and asked them to make a simplified version and in 9mm please? Ok, the US would have probably asked for a version in .45. 

Edited June 24 by Markus Becker

[RichTO90]

8 hours ago, Markus Becker said:

The M1 was supposed to be an interim gun. At 50 $ a piece it took still too much effort given the numbers needed. It was supposed to be replaced by the M2 but that was so much delayed that the M2 was skipped over in favor of the M3. 

WRT ammo, by the actual time the US military became sufficiently interested in SMG they seem to have been in the war already. So too late.

But the process could have started sooner. Mid 1940 when their mobilization began. It should have been obvious that more SMG were needed and that the M1928 would not be the weapon of choice. 

Though the most realistic alternative would be the British. They and the French started ordering as November 1939. Given the insane price, WI they had taken a M1928 to Savage Arms and asked them to make a simplified version and in 9mm please? Ok, the US would have probably asked for a version in .45. 

The Submachine Gun, M2 was not "delayed" it was cancelled after it was found  too difficult to manufacture given that it was expected to be a replacement for the more difficult to manufacture M1. It was actually quite a good gun as manufactured in prototype, but Marlin had trouble with the forged receiver and the performance of the manufactured types proved inferior to the prototype, so Ordnace decided to go with the stamped steel M3.

It was only "obvious that more SMG were needed" while the rosy view of the utility of the SMG lasted, which wasn't long for the U.S. Army. The Army requirement for SMG quickly changed as the hype got replaced by the reality that it was only useful in certain situations. In most Army T/O&E it was replaced by the M1 Carbine after 1942 and never became prominent again. About the only place the SMG remained was as part of the basic equipment in tanks and as a "pool" weapon for the Parachute and Ranger Battalion.

[Markus Becker]

On 6/23/2024 at 4:51 PM, bojan said:

 - it needed a lot of lathe work, but relatively little milling, which was most problematic one at the time. Compared to that Thompson was all milled.

OTOH, on the local SMG shooting tests M1A1 Thompson performed better than much worshiped MP-40, even through MP-40 was better SMG in practice 

 

 

 

Milling was problematic at the time because so much other stuff needed to be milled? Artillery ect....

What does that mean for a hypothetic American clone of the MP28 made in the early 1930? Still way cheaper to make than a Thompson and you can offer an M28 for 112,50$ with a filthy profit margin? 

[bojan]

Milling was slower method of fabrication than turning on lathe and good tolerances were much harder to do with mills than on lathe at that time period.

Yes, if done on same industrial base MP-18/28 will be cheaper than Thompson, but it is hard to imagine what would be more expensive than Thompson.

[R011]

In the 1930s, the US Army was not much interested in SMGs at all and had no budget to develop them anyway.  Neither was the British, for that matter.  When stuff hit the fan in late 1939 and they saw the Germans seemed to use them a lot, the only one in American production and available for export was the Thompson.

[Interlinked]

What was the M3 grease gun's place if the SMG was being phased out in favour of the M1 carbine?

[Markus Becker]

14 hours ago, Interlinked said:

What was the M3 grease gun's place if the SMG was being phased out in favour of the M1 carbine?

Was it? The carbine was 'supposed to be' the PDW of the non combat and non infantry units.

SMG were infantry weapons and for vehicle crews. Didn't a certain @Harold Jones still have one in his M60/M1? 

[Harold Jones]

There were 2 on every m60 series tank. When we got m1s they were replaced by an m16.  They were easy enough to store and carry, easy to clean and maintain, but I don't think anyone thought they'd be any use in combat.

[RichTO90]

Yes,the .45 Caliber SMG M3 became the standard onboard armament for combat vehicle crewmen...like the M1 was and the M2 was supposed to be. Otherwise, it was issued as a "pool" weapon - normally issued by commanders as they saw fit for specific tasks/missions . In the Ranger Battalion there were 18 assigned (6 per company) and 20 as "pool" weapons. After mid-1943 they were unusual anywhere else. There were 18 assigned as "pool" weapons to the Parachute Infantry Battalion and 20 to the Infantry Battalion, but 138 in the Armored Infantry Battalion.

[Interlinked]

Ah I see, so it was a completely different way of distributing these weapons.

[bojan]

Basically only US could afford such system in WW2. Post WW2, in the '50/60s French also used something similar, ~1/3 or the frontline infantry had SMGs and 2/3 had semi-automatic rifles as personal weapons, but there was enough SMGs (in IIRC Bn logistics Co) to rearm another 1/3 with SMGs, for close-in conditions fighting.

Edited June 28 by bojan