"251 armour and HMG fire" Topic

Hi
Just having a discussion/debate with a mate about how effective the armour on 251s was against small arms fire. We agree on most rifle fire would be ineffective but after that we are in disagreement over Bar/Brens and then 30cal Vickers 50cal etc

So came to THE place for the definative answer :-)

The 251 was reasonably proof against small arms fire (unlike the M3/M5) and BAR/Brens are no different to rifles although they have marginally longer barrels. The .50 cal would have no problem penetrating them at close range though. SFMGs, hard to say, they are still firing rifle calibre bullets, so probably not unless very close and/or flank/rear shot.

The 251 was designed to be resistant to small arms fire and shrapnel. .30 cal type weapons could penetrate it at closer ranges with AP ammo, while the .50 could fairly easily chew through it.

BAR, Bren, MG34/42, M1917, M1919, Vickers etc. used rifle caliber rounds fired at same (or marginally higher) velocities as same rounds fired from a rifle, so not a significant difference.

Heavy-caliber machine-guns such as the US .50 cal M2 or the Soviet 12.7 mm DsHK would have had significantly better penetration, and should provide something of a threat for a half-track.

Griefbringer

As mentioned, .30 cals would bounce, but .50 may penetrate at close range, but the sloped armor helps provide some protection from that.

Ok thanks guys – I won the 'debate' as I said it was only really HMG and then only from close :-)

Don't forget to consider the relationship of the firer to the vehicle since they are open topped….

.50 was (still is) actually a super-heavy MG. HMG should really refer to any water-cooled MG (they weigh a lot!) such as a Vickers or those big old Maxims the Russians put on wheels. Air-cooled MGs on tripods would be MMGs (medium machineguns); and bipod-mounted MGs are LMGs.

I am starting to more and more dislike the LMG/MMG/HMG division, especially the way many wargamers try to use it as the only classification for modelling the weapons.

I think a more constructive approach would be to classify the weapons by their separate technical factors:
- feed mechanism (strip, magazine, belt)
- mounting (bipod, tripod, carriage)
- cooling (air or water)

Griefbringer

Don, you're giving me a flashback to the most pointless email debate I ever had with someone who was determined my classification of MGs was profoundly flawed, even though I was using what the relevant armies of the day did!

I prefer to use the nomenclature in use at the time, the Germans only had light and heavy MGs, the British had light, medium and heavy MGs – which is why the Vickers gun manual is called 'Tactical notes on handling medium machineguns', although some diehards insist on calling anything which isn't on a tripod an 'automatic rifle'.

The real questions are:

a) is it set up for sustained fire
b) does it have significant AP capability.

HMG should really refer to any water-cooled MG (they weigh a lot!) such as a Vickers or those big old Maxims the Russians put on wheels. Air-cooled MGs on tripods would be MMGs (medium machineguns); and bipod-mounted MGs are LMGs.

No – See MArtin's response.

To add to what MArtin said. Heavy when you are talking about machine guns refers to the rate of fire and the ability to sustain it rather than how physically heavy the ordnance was/is.

Isn't it also to do with indirect fire sights?

Just a thought.

Gary: Sorry 'bout that.
Martin: How did the British distinguish between a MMG and a HMG?

CCollins: probably.

I'm not sure now where I came up with my classifications. (Maybe a little voice whispered to me?) But I agree that a water-cooled MG was not called a HMG just because it weighed a lot, but also because it could be used for sustained fire. Anyway, it was not (necessarily) a question of the caliber of the slug.

The problem with using the nomenclature of the time is that each country used the same terms for different things, and different terms for the same things. For instance, the Germans put an air-cooled MG on a tripod and called it an HMG. (What did they call their old Maxims? I'm sure they used some.) The US put an air-cooled MG on a tripod and called it an LMG.

Oh, well. Didn't mean to hijack the thread. Sorry, THWjunky.

No worries Don – had my info the following debate is just icing on the xmas cake :-)

I usually differentiate by how they fire:
Clip fed
Belt in magazine fed
Belt fed
Belt fed sustained fire

Then if the rules need detail break the weapons down within those bands by 'special rules' etc. But that is just my take :-)

In my home-grown skirmish rules I allow automatic weapons to have several modes of fire, depending on what their theoretical ROF is and what position they are fired from. So an MG42 can technically be fired from an assault position, a bipod, a tripod or a fixed mount. However, in less braced positions (i.e. assault mode) the effective range is negligable (say 6-12 inches), increasing as the MG is fired from a more stable platform. I find that it replicates recoil quite well, plus I don't have to make arbitrary determinations as whether a weapon is an MMG or an HMG. The player simply fires the weapon according to circumstances. Most players realise that the MG has a better range braced, so set-up with a bipod/tripod almost immeditely and start laying down some covering fire.

Anyway as for armour penetration I asked a similar question about MG fire against MKIV tanks on the WWI board. The MKIV has similar armour thickness to a 251 and the thinking was that AP rounds would cause problems, even if it was just internal spalling. I never did get a satisfactory answer though as to how a HE blast (not AP or specialist AP HE rounds – just an ordinary HE blast), would do against armour. Say a heavy HE shell lands 15ft away. Would that cause any significant problems to the occupants of the vehicle? I assume as said shell lands closer the more damage, but I got the impression that only really a direct hit would knock an armoured vehicle out. And how heavy a shell are we talking about? The main WWI anti-tank round was the German 77mm HE shell and most contributors to the thread said a direct hit would mangle a MKIV. But what about an indirect hit? How would it do against a 251?

"Martin: How did the British distinguish between a MMG and a HMG?"

A HMG was something like the .5" BESA, which had significant AP capability it was the main armament on some light tanks).

"The problem with using the nomenclature of the time is that each country used the same terms for different things, and different terms for the same things. "

Agreed. As mentioned above it partly depends on the level of game you are interested in. IN low levle tacticla games I classify weapons based on:

mount (bipod vs tripod)
feed (belt vs mag or strip)
AP capability
and that really hard one, is it an MG at all. I don't think a BAR is an LMG, so it doesn't get a significant beaten zone, but it does get a firepower advantage. Quick change barrel? mag capacity? judgement call really.

What makes MGs lethal is that long deep beaten zone, interlocked with their pals to generate flanking fire on assaulting infantry.

Don't worry Don, I was typing with a smile!

I believe the Germans classed their Great War era 08s as HMGs same as the successor MG34 when used on a tripod mount. As mentioned up above it was more the idea of sustained, prolonged fire that made it 'heavy', though the physical weight was substantial.

I reckon you always have to fudge it a bit somewhere, the Vickers is a medium in Britspeak, but does exactly the same job as any tripod mounted heavy. The US .50-cal was pre-war deployed for anti-tank and anti-aircraft use, so was more of a light cannon in some respects than a HMG. The M1919A4 is a bit better than your average box fed LMG re sustained fire, but a lot heavier to lug around, while the BAR is…well, let's not be judgemental.

Most of the armies I can think of had a light fire Squad/Section weapon and a heavy fire tripod mounted weapon for Company/Battalion support with no 'medium' in between.

Gary

@General Monty
For what it is worth, a 77mm HE shell landing within 15 feet of a SdKfz 251 would very rarely produce crew casualties in Over There! (for which I did a significant amount of research regarding armour penetration). Something like a 2% chance, give or take (an American M3 half-track is actually more vulnerable here). A direct hit would easily penetrate the 251, however (in OT, an average 20mm of armour penetration is reasonable for a 3" shell, while armour of 50mm or more thickness would be absolute proof against such an attack). Data for this stuff can be hard to find, so I suggest starting where I did; finding penetration data for WW2 bombs (I.E. those dropped from fighter-bombers). Compare the high explosive content of a 50kg bomb to an HE artillery shell and you start getting an idea of how effective HE would be. Note, however, that most bombs would hit at a flat angle, while artillery shells will likely hit around a sloping angle (which may or may not have a significant effect). Then find out what you can about actual HE shell performance and cross reference these results.

@Gary Kennedy
Adding to your point, it's also good to recognise that the actual German word "schwer" doesn't cleanly translate into the English sense of "heavy". It often implies difficult, dire, serious and so on (which seems to support the idea that sMG implies sustained fire, while lMG implies light, tactical use).

As for the terminology, it might be good to remember how things were in the beginning of the WWI – back then, machineguns were simply called "machineguns" and were water-cooled weapons on sturdy mounts (tripods, carriages) firing rifle-caliber ammunition. None of these fussy light/medium/heavy sub-division.

Even by WWII a number of armies (eg. the Finnish) kept on calling those same weapons simply as "machineguns" without feeling any need to cram some sort of medium/heavy term in front of it.

But what about an indirect hit? How would it do against a 251?

With indirect hit, what you need to worry about is the shrapnel. Which is nasty against flesh but not all that great in penetrating armour (shape, mass and velocity) and often could be stopped by a simple tin hat. Most armoured vehicles were designed to withstand shrapnel.

Of course, very close misses and heavier caliber artillery could prove more troublesome.

Griefbringer

With a direct hit, or very close near miss, an artillery round (the bigger the better) might kill, wound, and/or incapacitate the crew of a tank or APC with concussion alone. Not so? Further, it might damage the engine enough to stop it running (e.g. disconnect a fan belt or fuel line). Finally, the threat of such things might cause a crew to retreat or panic (though probably not bail out) even when not directly hit.

In an fairly realistic old WWII movie -- forget the title, but the one about the defense of Bastogne, with Van Johnson -- a new recruit (Marshal Thompson) asks what to do if attacked by tanks, and the old Sarge (James Whitmore) says, "we put our heads down and call for artillery."

It was "Battleground" Don – had to Google it, but I recall a few of those late 40s early 50s war films had that edge to them. Always wondered if that was because some of those involved in the making had been there in real life.

Rule of thumb on a .50-cal is that if it's light enough to fly or roll on wheels, the rounds can penetrate. Modern materials throw a wrench in the works, but there are more modern rounds (SLAP – A .50-caliber sabot, for example) that tip the balance back again. Standard modern .50 round is API (armor piercing incendiary), but ball (solid slugs) is still in use and was probably more common back then (although API is probably the best choice against aircraft).

High Explosive follows the inverse square law. Doubling your distance from the explosion quarters the energy absorbed. That's why all of the mine-proof vehicles are so high off the ground. Fragments are ballistic objects. Increasing distance decreases your chances of being struck by a fragment more or less along inverse-squared lines, but the fragments themselves lose energy based on air resistance (the good news is that big, jagged fragments lose energy more quickly). Individual hand grenade fragments can be thrown up to 100 meters, safe distance for 155 artillery shells is about 4 times that (SAFE distances, not effective kill and casualty radii, which are much smaller).

I believe the standard load for .50 caliber MGs was alternating rounds of AP, incendiary and tracer, or something like that.

Gary: I suspect the writers of many of those old movies were veterans, even if the directors, producers and actors were not.

Gary and Don Try watching any of the movies written and directed by Sam Fuller up to and including "Big Red One" of the late seventies or early eighties. Sam was a vet, BR1 was a fictionalised biography, and the realism is obvious. Fatman

One of the books about churchills describes a training incident.
They were advancing behind a 25pdr barrage when one of the shells fell short and hit the "horn" of one of the tracks.
No noticeable damage and the tank simply carried on.
25pdr are 88mm, and whilst not heavy artillery not exactly lightweights.