January 1936: British army, you run the show

[Shortround6]

What is confusing to many people, even if not you, is that the Germans used both style weapons and at times, in part due to vehicle shortages, mixed then up. This was not helped by the Germans using two slightly different names for rather different roles for the SP AT guns.
This has tended to mix up the actual roles of the vehicles in other armies for many observers/commentators.

Many web sites/wargames tend to lump them all together.

The original Stug IIIs were artillery that could accompany the infantry in the assault. However the first units used artillery type sights for both gunner and commander, had radio receivers only, and EVERY battery had at least one dedicated armored forward observer vehicle (the Sd Kfz 253). The Forward observer vehicle had a higher priority than the Sd Kfz 252 ammo carrier and most were built before the SD Kfz 252 production run. Now since the reason for using forward observers is so the gun/vehicle can sit back from the front line and shoot without getting shot at (much) it would seem it's primary job was NOT to lead the infantry in or even follow them at a few hundred meters distance. The fact that they could added flexibility to the German tactics. The other early German SP gun was the 150mm sIG 33 and in no way, shape or form should this thing have been operating anywhere where enemy infantryman could get behind it.

Granted they only built 12, more as a proof of concept than as what they considered even close to ideal.

Bundles on left rear fender are actually ammo storage.
What confuses things further is that they would use the same "gun" for a different role.

On the MK III chassis max elevation was restricted to 25 degrees so max range was restricted compared to the MK I, MK II and Czech 38(t) chassis self propelled versions but the closed top (not to mention back) , heavier armor and a MG that didn't require a crewman to stick his upper body out of a hatch or above the superstructure wall to use meant the vehicle actually had a different role.

 

[tomo pauk]

Hmm - how useful would be the 6in howitzer installed on a 25-30 ton British tank, for use, mostly, in direct fire mode, like that StuIG 33, or the Pz-IV based Brumbar? Maybe on the Churchill (unless we figure out a better 40-ton tank here ?
Granted, the size and ammo would be greater in the British weapon than at the German 15cm.
Or maybe 4,5-4,7in gun howitzer instead, not unlike the SU-122?

 

[Shortround6]

Hmm - how useful would be..........

Pretty useful........IF the British had faced a Stalingrad or Sevastopol type defensive situation in North Africa or Italy.

Of course if you have a decent heavy artillery park and decent logistics to begin with you don't need a few dozen one trick pony vehicles to try to paste over some of your shortages.

 

[Shortround6]

To try to put some of these oddballs in perspective.

Year..............................1941............1942...................1943

MK III chassis..................2213...........2958...................3379
-stugs............................650?............600?...................????
# of 150mm MK III............0 or 12......12 or 24................0
MK IV chassis...................467............994.....................3822
38(t) chassis....................678............652.....................1,008
-SP guns..........................0.............394-444?...............750?
150mm 38(t)....................0................0........................200???
Sturmpanzer IV................0................0..........................60?


Germans may have found the 150mm heavy assault guns "useful" but hardly critical.

The ones on the 38(t) chassis were pretty much conventional SP artillery guns.

rear panel was folded down in "action" and tray holding 3 projectiles provided a convenient work space for fitting fuses and prepping the ammo.

Niether version of the 38(t) was suitable for actually getting in the middle of a fire fight.

When trying to figure out how to "improve" an army, air force or navy the first things should be figuring out if they were deficient in any basic combat needs/requirements. Trick planes, tanks, guns of limited utility would wait until the basic needs are met.

 

[tomo pauk]

Now, about the things that were supposed to kill tanks. Anti-tank rifles - any point in those? Grenade launchers, both rifle-based ones and of greater power, like the Bazooka, PIAT or Panzerfaust?

 

[tomo pauk]

The penetration figures for the British guns:

British Anti-Tank Gun Penetration tables

 

[Shortround6]

Now, about the things that were supposed to kill tanks. Anti-tank rifles - any point in those? Grenade launchers, both rifle-based ones and of greater power, like the Bazooka, PIAT or Panzerfaust?

We are talking on the platoon/company level?

Anti-tank rifles (anybody's) tended to crap out once the armor gets to 30mm or better. So in hindsight an awful lot of effort and money was spent on them for not a lot of return. The British and Russians probably got the best return on their AT rifles. The British, in part, because one of their main enemies in 1940-42, Italy, had about the thinnest, weakest armor on their tanks on average (the Carro Veloce CV-33 really pulled down the average). The Russians had two things going for their AT rifles, One of the more powerful cartridges used in common AT rifles and again, somewhat weak armor on the majority of German tanks, at least in the first 2 years of the Russian Campaign. The 14.5mm being able to just penetrate the side 30mm armor at reasonable (?) combat distances given a decent impact angle. Of course shooting at the sides/backs of tanks means they have already over run your position.

The next question is how much do you want to bend history. The shaped charge effect was pretty much a lab curiosity/parlor trick called the Monroe effect (at least in English speaking countries) until a couple of Swiss guys figured out how to weaponize and tried to sell it. Unfortunately for them a British military attache at the demonstration (or so the story goes) recognized that they were NOT sell a 'a new and powerful explosive" but were using the Monroe effect in their demonstration. This was going on in the late 30s, the Germans used hollow charge demolition charges against Fort Eban-Emael and the British were issuing the No 68 rifle grenade in the middle of 1940. Earlier introduction of hollow charge weapons requires not just different choices being made with information available at the time but information not really available in 1936-37-38-39. It took teh US until 1943 to get the Bazooka to be a reliable and effective weapon, early versions being bad enough that they stopped issuing Bazookas for while until the problems could be sorted out.
The British tended to sour on (not favor) the shaped charge after their first experience with it and only used it when no other solution seemed to offer any chance of success.
Perhaps with a bit more development work ( a better design of cavity and liner) their experience would have been better.

However once the British leave France, the utility of very short ranged AT weapons falls off considerably, and doesn't really pick up until the invasion of Sicily (Far East excepted).

The PIAT was a miserable weapon to work with but had the advantage of a very low firing signature and the ability to be used from a confined space (small room/bunker) which the Bazooka and Panzerfaust could not.

 

[vinnye]

I think you need to train the anti tank troops to aim at the side of the tank as much as possible and avoid the frontal armour. Taking a track out or a wheel to disable the tank rather than knock it out completely is the objective. I think a lot of crews would bail out pretty quick if their tank was immobilised?
Anti tank rifles although heavy and having a big recoil give infantry a bit more distance between them and the tank compared to a PIAT etc.

 

[Shortround6]

Most of the infantry Anti-Tank 'stuff' is sort of a last ditch weapon. If the enemy tanks stop 200 yds short of your position and proceed to shoot it up with cannon and MG fire while their infantry creeps forward all the Bazookas, Panzerfausts, Piats and for the most part AT rifles are pretty much useless. Only if the enemy tanks try to drive through the defensive position do they become effective and having something that shoots even 75 yds beats the heck out of running up to a tank and trying fling a demo charge onto it's engine deck or into the tracks.
In the desert (or in places on the Steppes) the infantry AT weapons weren't very effective. In Forest/Jungle or towns/cities where the infantry could 'ambush' the tanks they were a lot more effective. The infantry had places to hide and the tanks ability to maneuver was greatly restricted. They often had to come down certain roads/tracks or go hundreds of yards out of their way (with trees/buildings in the way so they could not support each other).

Trouble is sometimes the tanks could do terrible things to the defenders in minutes if not stopped. In the desert the tanks sometimes turned at the first line of defense and drove down it machine gunning the trench, line of weapons pits and literally driving over guns and positions with the tracks. A second defensive line now gets a nice flank shot at the tank/s but the men in the first line are in deep trouble. Some times the tanks broke left and right at the same time and rolled up the lines while a second formation of tanks headed for the second line of defense, a several hundred yd wide gap really allowed the enemy infantry access to the position. Granted this is sort of textbook and seldom happened in perfect order.
But telling the infantry to "just wait" for the side shot takes favorable circumstances and determined/brave men.

Bailing out tended to vary with the crews and the threat. If you are a British tanker and an 88 or 75mm takes off one of your tracks you bail out as fast as possible before another round hits the tank. If you threw a track making a sharp turn and have a bunch of MG bullets pinging off the tank you stay inside, try to call for help and try to locate the MG and shoot back. In the early years the tank shells were too small to be assured of "killing" tanks even with a penetration. Kill or wound one or more crew members yes, but not the entire crew or render the tank totally out of action. Many tank crews and AT gun crews continued to shoot at tanks they hit until they saw the crew bail out, flames or large amount of smoke or saw guns point skyward or towards the ground. (British tanks used the gunners shoulder to control elevation). Too many tanks had come back to 'life' after a brief period of time and started shooting again.

Best AT defense for infantry is battery of AT guns occupying the same ground

 

[tomo pauk]

The next step from a small caliber tank and AT gun? I do favor the 3pdr Vickers, so the next step might be a new gun, designed around the 3in AA round. That one fired 12 lb shell at 750 m/s, the 16 lb shell was fired at 610 m/s. Of course, the new ammo types need to be issued as they are developed.
The AP capabilities would be on par with German 7,5cm L/43 and L/48 guns, in case similar type of ammo is used; much better once the APDS is introduced. Far heavier HE shell than the 6pdr along with better penetration, of course. Against the 17pdr, or a similar 'hi-power' gun, it would fit into smaller tanks/AFV (25-30 tons) or towed carriages. The ammo count would be greater also.

For something bigger - the gun about as powerful as the 17pdr (4 kg of propelling charge), but of the 88mm caliber. Not that I'm advertising copying the famous German gun, it is simply that the 25pdr was of that caliber, and this big gun will fire it's HE and other non-AP shells, on a reduced propelling charge if needed (in case lower quality steel is used). The round would be looking like the 17pdr ammo, necked-out a bit.

 

[tomo pauk]

Let's get back to the Littlejohn adapter. It did have it's shortcomings, 1st and foremost the need to be removed if the full-bore shell is to be fired from the gun. That would make the use in tanks very problematic, less so for the towed AT guns; no problems if the aircraft is carrying the gun. Another problem is a somewhat late introduction (from the above linked site):

This was known for security reasons as the "2pdr littlejohn", the Mk I entered production in January 1943 and the Mk II was approved in May 1944 to improve performance against spaced armour.

On the benefits. The penetration was more than doubled vs. the 2pdr with plain AP shot at 1000 yds and under, and almost doubled vs. the APCBC shot. Unfortunately, seems like the British never developed/issued the APCR for the 2pdr gun.
The penetration of 71mm at 1000 yds, against the rolled homogenous armor at 30 deg, was only surpassed by the 6pdr gun if it was outfitted with longer barrel (50 cal long) and APCBC ammo or better. The Germans introduced additional armor plates, of face-hardened armor, against whose the plain AP shot was less efficient, unlike the APC or APCBC sots.
Another benefit was the earlier introduction than the APDS shot for the 6 pdr, meaning there was a way to have a substantial increase in AP capability before the APDS is perfected. Increased MV also meant the increased hit probability.

For the 3pdr Vickers with the Littlejohn adapter (ammo called APSV), we might assume a 10% increase in the penetration vs. the 2prd with same, ie. penetrating 75-80 mm at 1000 yds, at 30 deg vs. the 'MQ' plate? An earlier introduction would help it, of course. The penetration would be somewhat lower without the adapter, of course, but can be used it on the tanks/AFV, as the APSV 2pdr was historically used sometimes.

 

[Shortround6]

A lot of the armored car crews which had the Littlejohn adapter simply fired the ammo with out the adapter and it pretty much acted like APCR shot. They lost a bit of velocity but the ability to switch ammo ( AP or HE) without having to get out of the turret and crawl out to the end of the barrel was considered a fair trade-off. By the time the Littlejohn and ammo was issued the NA campaign was over and the chances of long range shots (1000yds or so) was very much smaller in Italy and France so the extra penetration at longer ranges with the streamline projectile (after being squooze {new technical term ) wasn't missed. Penetration at short range is hardly affected except for the loss of initial velocity due to no adapter.

We are back to the cheap British ammo. There was no technical reason that APCBC ammo could not have been issued with the first 6pdr guns (or even 2pdr guns). APCBC or variations on it had been used in WW I by British naval guns down to 6in.
Making APCBC projectiles shouldn't have been any more expensive than making APCR projectiles or projectiles that smooshed down in diameter as they went through barrels/adapters that changed in diameter.

 

[tomo pauk]

The Commonwealth armies used quite a number of 'Kangaroos', the tanks/AFVs turned into APCs. The main problem with those was that infantry was expected to jump over the sides to join combat, not a very healthy proposal for the grunts. Also they were not protected from above, a lucky shot was able to wipe a complete dismount.
Once the needs for the 1st line tanks and SP artillery are met, APCs should be next on the list?
The most straightforward might be the conversion of the American tanks, hopefully done in Canada? Cram the engine from the rear into mid position, like it was done with the M12 gun carrier. Install the rear-facing ramp, of course, also install the roof. Also the hull lengthening might be a good idea, should offer more space at the back.
The similar conversion could be attempted with M3/M5 light tanks. Also a conversion from the lighter cruiser tanks that Ive proposed earlier; a new build also.

This might be interesting: link

 

[Shortround6]

You can pretty much forget the light tanks, unless you add a 3rd bogie to the chassis.

 

[Shortround6]

duplicate

 

[tomo pauk]

I did, years ago... In the middle is the version with a smaller hull extension.

 

[tomo pauk]

The earlier introduction of a bigger, but not too big a gun (like the modern gun designed around the 3in AAA cartridge) might allow for easier, earlier and more numerous conversion of the US tanks/AFVs once their armament is seen as lacking, mostly in AP capabilities. The introduction of the APSD shot for the US 3in/76mm should be a straightforward job.

 

[Shortround6]

The introduction of APDS for US guns had a limit because there was a limit to the amount of tungsten cores. The need for APDS shot in the US guns (basically the 3in in the M10 tank destoyers and the 76mm armed Shermans) wasn't quite as great as might be believed because at close range (say under 500yds) the difference in penetration between APDS and APCR isn't that great and, subject to availability, the APCR shot for the US guns had already been designed, approved and manufactured. While it is possible to get long shots in western Europe the opportunities are a lot less than the opportunities in the desert or on the plains/steppes of eastern Europe. The longer effective range of the APDS was less needed. The US also believed (with some justification in the first few years) that APCR was more accurate than APDS. And here you hit a possible problem. Some rounds/projectiles are more sensitive than others to changes in velocity and rifling twist in regards to accuracy. Using slightly modified British projectiles in American guns might have been like getting a duck to swim or it might have been like getting a fish to fly.
The US didn't shift to APDS shot in US tanks until they installed the British 105mm cannon in the M-48 to make the M-60 tank. Doesn't mean they were right

The US 3in/76mm high velocity guns fired 15.4 pound projectiles at 2600fps compared to the 77mm gun in the Comet firing a 17lb projectile at 2600fps. The British gun was better but is a 10% increase in shot weight, worth a re-gunning program? That leaves changing the original 75mm gun on the Shermans as the only possible worthwhile re-gunning program. And sticking the 77mm (or an earlier version) might not be that much easier than sticking in the 17pdr. It may be a lot easier, I don't know. Americans used a whole new turret when they went to the 76mm.

 

[tomo pauk]

That leaves changing the original 75mm gun on the Shermans as the only possible worthwhile re-gunning program.

The British didn't received the 76mm armed Shermans in more than token number anyway? The 75mm versions were in vast majority, up-gunning of these with the proposed gun would bolster both HE and AP capacity (even before the APDS is introduced).

added: FWIW: the US tests of the 17pdr on the Sherman: link

added 2: the British were able to install the 77mm in the Comet, despite the restrictive internal mantlet. The 17 pdr was a no-go there.

 

[tomo pauk]

The self-loading rifle for the British, and/or the automatic rifle? The automatic rifle would need an 'intermediate cartridge', though.

added: seems like the Germans used the Diglykol propellant for their 7,5 cm Pak 41 already ( link) (re. the 'R4M on steroids').