Lewis Gun

[Sgt Joch]

As to why the Germans bumped up the max ROF, I do not know, but in actual battle conditions, the effective ROF was about the same, apparently 150-154 RPM when used as a LMG.

http://www.lonesentry.com/articles/intelligence-report/use-of-mg42.html

 

Edited July 15, 2016 by Sgt Joch

[JasonC]

Erwin - one cheap to make gun across the whole force, was the primary motive for the MG42.  The high ROF was certainly useful in an aircraft or anti aircraft role, for the reasons already given above.  By late war, The Germans didn't consider it sufficient caliber for any anti material purpose including AA, relying on 20mm cannons, 15mm MGs, and late war on 30mm cannons for that.  But early midwar, they had lots of MGs in the skies, on fighters and (flex mounted) on bombers, not just ground LMGs in the infantry.

[Duckman]

On 2016-07-15 at 8:53 AM, Erwin said:

Understood.  But that doesn't address the question re what was the military's reasoning for wanting a faster ROF weapon?  Presumably the MG 42 could have been manufactured to have a lower ROF.

Wiki has a pretty good answer:

The MG 42's high rate of fire resulted from analysis concluding that since a soldier typically only has a short period of time to shoot at an enemy soldier, and muzzle rise quickly throws off initial aim, it was imperative to fire the highest number of bullets possible in the shortest time to increase the likelihood of a hit before the recoil overcame the inertia of the gun and pushed the aiming point upwards. The disadvantage was that the weapon consumed exorbitant amounts of ammunition and quickly overheated its barrel, making sustained fire problematic. Thus, while individual bursts left the weapon as highly concentrated fire at 1,200 rounds per minute, the Handbook of the German Army(1940) forbade the firing of more than 250 rounds in a single burst and indicated a sustained rate of no more than 300–350 rounds per minute to minimize barrel wear and overheating, although the excellent quick-change barrel design helped a great deal.

Source: https://en.wikipedia.org/wiki/MG_42

This seems to explain why they kept increasing ROF, from about 600 RPM in its MG 30 ancestor to 1200 for the MG 42. The idea was burst fire, and I assume this was taught to gunners although actual practice might differ of course.

I also remember something about the US fiddling with the idea of copying the MG 34/42, but this came to nothing (which was actually better than the severly botched Hispano 20 mm copy) and larger numbers of 30 Cals were fielded instead, somw with bipods. Experienced units also acquired even more automatic weapons informally..

Edited July 16, 2016 by Duckman

[Erwin]

Well yes, that was my understanding - that the Germans wanted to have a lot of kinetic material heading downrange in the shortest possible time.  Others are saying that is not actually effective and that lower ROF is better.  My question to them is were the Germans just plain wrong in their assessment of the need for the MG42's high ROF?

[panzersaurkrautwerfer]

51 minutes ago, Erwin said:

Well yes, that was my understanding - that the Germans wanted to have a lot of kinetic material heading downrange in the shortest possible time.  Others are saying that is not actually effective and that lower ROF is better.  My question to them is were the Germans just plain wrong in their assessment of the need for the MG42's high ROF?

Yes.  Yes they were.  It proved impractical in regards to ammunition capacity, had a very detrimental effect on the service life of the weapon, and did not deliver performance proportional to that cost.  Looking at post war designs somewhere between 600-700 RPM looks to be about standard for infantry machine guns, with few if any attempting to replicate the 1200 RPM of the MG42.  The MG42 was more relevant not for weapons performance (although the rapid fire did leave an impression on folks being shot at by it) nearly as much as showing the benefit of a small squad portable belt fed MG.

As to directly copying the MG42, it was attempted, but from my reading adapting the mechanism to accept the longer American rounds was proving to be problematic and the project just did not offer enough of an advantage to encourage pursuing the weapon much further (or in effect, more M1919s>time and resources spent trying to make an American copy of the MG42 that might really not make much of a difference).    

[AttorneyAtWar]

While its nice to throw around the 1200RPM line when talking about the MG-42 it was rarely ever used to its full potential in that regard. German soldiers recognized how stupid it was ti fire at 1200RPM for all the reasons listed above. I believe it was even limited to 800-900 during the war or was that just in training?

[c3k]

Tell me again what the MG3 ROF is? And why it has three different bolt weights?

[panzersaurkrautwerfer]

13 minutes ago, c3k said:

Tell me again what the MG3 ROF is? And why it has three different bolt weights?

The Germans started and lost both world wars.  They're pretty bad at learning from mistakes.

In all seriousness, likely because it's an evolution of existing equipment that worked well enough to not make a total changeover attractive.  The MG42 wasn't a "bad" gun, it's just very high ROF left so much of an impact on the Americans, Russians, French, Belgians, and virtually every other major non-German gun maker that absolutely none of them opted for over 1000 RPM infantry machine guns.

The MG3 is a special case because it's an evolution of the MG42, and it's not "bad" but every clean slate machine gun post world war two seems to follow a much slower ROF model, and that can't simply be because inferior not Germans cannot handle the powar or something.  

[c3k]

Well, there seems to be a new machinegun about to supplant the MG3...the HK121, known as the MG5. MG5 seems to be a lot more "standard"; no more recoiling barrel and dual lugs. The HK manual states the HK121/MG5 has 3 ROFs: 640, 720, and 800. It uses a standard rotating bolt/gas operation system. I "assume" the ROF is controlled by changing the gas port.  I'm not sure what the status of the MG5 program really is...e.g., has it entered production and is it replacing the MG3? Shrug... It represents a solid move towards the ROF used by everyone else.

[JasonC]

Erwin - asked and answered - yes, the Germans were just plain wrong.  Why is this hard?

[Duckman]

13 hours ago, panzersaurkrautwerfer said:

The MG42 was more relevant not for weapons performance (although the rapid fire did leave an impression on folks being shot at by it) nearly as much as showing the benefit of a small squad portable belt fed MG.

That's pretty much it. The other major belt fed LMG was the M1919, which is 2,5 kg heavier and has a tripod in most versions.

As for the tactical impact of LMGs, already at the Somme German after action reports mention how the Lewis gun was a pest because even a small group with one could set themselves up in a house or trench and turn it into a strongpoint in no time. Standard MGs like the Vickers or Maxim were too heavy and bulky to accompany the first waves.

With the MG 34/42 you get that on steroids: it's compact enough to sneak in anywhere, has a very short setup and redeploy time with the bipod, and endurance with the belt feeding.

Edited July 17, 2016 by Duckman

[Duckman]

As for postwar developments, once squad members get automatic (or even semiautomatic) weapons the firepower equation changes a bit with less need for an ultra-high ROF MG. The WWII German squads built around the MG 34/42 had a four-man MG element with three designated ammo bearers, and this obviously becomes a less attractive tradeoff if every squad member can carry an automatic weapon.