schnuersi said:

       stancrist said: LOL. There are a great number of soldiers who are neither infantry nor AFV crewmen.

No but they are vehicle crew... allmost everybody drives around in a vehicle and most task are even conducted while in the vehicle. If the vehicle is armored or is unimportant.

Well, if you're going to define "vehicle crewman" as any soldier who drives a motor vehicle at some time during the year, then that means even infantrymen are vehicle crewman and should have a PDW instead of a rifle or machine gun...

schnuersi said:

       stancrist said: Such as?

Engineers, medics, artillery men, signals guys, mechanics the list goes on.

US Army medics are armed with a carbine, but it does not seem to impede them in performing their duties. 

And I see no reason why a carbine would be any more incompatible with the other jobs than would an MP7.

schnuersi said:

       stancrist said: Can you cite any examples?

For non infantry soldiers getting jumped while they did not have a rifle nearby? In the training manual of the German army used to be such examples. It also was a common occurence during training. People who where issued rifles frequently left them in their vehicle or put them somewhere where they would not get lost and ended up being unarmed in a supprise contact.

I meant examples from combat.  Peacetime training exercises don't matter.  In peacetime, soldiers do stuff they probably wouldn't on the battlefield.  During one deployment to the National Training Center, some of the guys in my battalion stowed folding beach chairs and coolers full of beer in the bustle racks of their tanks, then "kicked back" and relaxed with a cold brew in the evening.

schnuersi said:

But you can easily google pictures of basically any German support arm during WW2 and usually you see a peculiar absent of small arms when the non infantry soldiers do their work. For example artillery, AA gun and AT gun crews.

That's not even a little peculiar.  That's actually quite typical.  You see the same absence of small arms in most WW2 photos of US artillery in action.  For example:

It's still the same in the 21st century.

YouTube

US Marines Fire Howitzer 155mm in Afghanistan

US Marines Fire M777 Howitzer 155mm at enemy targets in Afghanistan. The M777 howitzer is a towed 155 mm artillery piece, successor to the M198 howitzer in t...

It’s almost like those redlegs put their rifles down out of the way to operate the guns. Just like they’d put down any slung weapon. Most likely they would rather remove a holster and pistol as well; belt holsters, sidearms and spare mags still get in the way when you’re moving around.

Engineers are vehicle crew? I must let my engineer acquaintances know that. 

DavidPawley said:

It’s almost like those redlegs put their rifles down out of the way to operate the guns. Just like they’d put down any slung weapon.

Yup, it's exactly like that.

I agree they would put down any slung weapon, even one as relatively small and light as the MP7.

DavidPawley said:

Most likely they would rather remove a holster and pistol as well; belt holsters, sidearms and spare mags still get in the way when you’re moving around.

Hard to say for sure.  It looks like the M1 carbine was the standard personal weapon for artillery gun crews in WW2.  https://youtu.be/1QgXuhv7-54?t=1501

I only found one photo showing an artillery man who appears to have a holstered pistol (at far left, below), but he is not one of the ammunition handlers.

Position of the slung weapon may be dependent on the chances of the enemy infantry suddenly popping out near your position

One thing is manning a howitzer or any other artillery piece well back of the actual front line, and another pushing it way up front in the infantry support role, or while defending the forward position

stancrist said:

Well, if you're going to define "vehicle crewman" as any soldier who drives a motor vehicle at some time during the year, then that means even infantrymen are vehicle crewman and should have a PDW instead of a rifle or machine gun...

No, my definition is everyone who conducts his main task or parts of his main task inside a vehicle.

stancrist said:

US Army medics are armed with a carbine, but it does not seem to impede them in performing their duties. And I see no reason why a carbine would be any more incompatible with the other jobs than would an MP7.

Most medics ride around in vehicles. Often even armored ones.
For the few that don't the real question is what does a carbine do to help them in their main task... answer: it gets in the way. A PDW also will get in the way but less since its smaller.
You have to die one death. Its about the optimal compromise.
Since there are vehicles everywhere there are GPMGs everywhere. In the past on pintle mounts nowadays often on RWS.
So what is the point of issuing carbines or rifles? The PDW is absolutely sufficient to buy time until a GPMG or heavier weapon can chime in.

stancrist said:

Peacetime training exercises don't matter.

I disagree. Soldiers tend to behave in theatre as they did in training. At least until they learned from experience that this is a bad idea. At this point its to late for some.
I do agree that its not 100 % the same.

stancrist said:

During one deployment to the National Training Center, some of the guys in my battalion stowed folding beach chairs and coolers full of beer in the bustle racks of their tanks, then "kicked back" and relaxed with a cold brew in the evening.

Great example... German soldiers do that in theatre. Of course details matter.
You still put out sentries etc but the guys who are not involved in any active tasks can lean back a bit and enjoy a sort of closing time. A carbine really gets in the way when sitting down and trying to relax a bit. A PDW much less.

stancrist said:

That's not even a little peculiar. That's actually quite typical. You see the same absence of small arms in most WW2 photos of US artillery in action.

And now we jump to modern times and there is no towed artillery anymore. Artillery men are AFV crews just like mortar teams. The only thing remotely comparable to a traditional towed artillery piece in the German army are the mortar teams of the airborne units who use light trucks to carry their mortars around and actually have to set them up.

DavidPawley said:

Engineers are vehicle crew? I must let my engineer acquaintances know that.

Just a few examples.

I don't know how you think modern engineers do their work? Lots of people with shovels?
The main mode of transportation of the German engineers is the Fuchs APC.
Except for the speciality engeneering companies of the airborne and mountain brigade the engeneering units are all fully mechanised.

mpopenker said:

Position of the slung weapon may be dependent on the chances of the enemy infantry suddenly popping out near your position

Looking at pictures with German troops from WW2 it mostly seem to depend how official the picture was. The staged, official propaganda pictures allways show soldiers in perfect uniform with rifle on the back. The snap shots taken during combat allways show very sloppy uniforms and no small arms nearby.

I took a look at the Soviet artillery photos from the WW2:

as you can see, it's a fair mix of people with and without small arms. I think the larger artillery caliber is, the less you will see small arms around it.

At least, most Soviet 45mm and 76mm AT crews are shown carrying their issued small arms during the action, which should be of little surprise, I think

mpopenker said:

At least, most Soviet 45mm and 76mm AT crews are shown carrying their issued small arms during the action, which should be of little surprise, I think

Just did some quick search of the internet. In the not representative sample i also found that the amount of small arms carried seems to be linked to gun size. For the 3,7 cm Pak often the crew is seen with rifles. For the 5 cm Pak seldom and allmost never for the 7,5 cm Pak.
My guess is is there are several faktors at play. The larger guns are usually moved by vehicle. They are also more difficult to bring into position. It requires more labour. The ammo is larger and heavier.
Its also important to mention that a German AT platoon of WW2 has an MG section for close in defense.