Why does the German Army like 20mm auto cannons so much?

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Neither system is healthy for enemy infantry!
Bradley gunners are trained one sensing round, correct and fire a 3 round burst, then final adjustment and a 4 round burst. Assume the sensing round is a complete miss, then you still have 7 glowing baseballs intering the proximity of the enemy troops, and they blow up like grenades at impact.
Not really sure about the Marders, figure two bursts of around 8-10 each, 16-20 smaller explosions (just a guess, they gotta keep a eye on ammo use too)

In either model, lots of stuff going whizzz BANG around the bad guys and lots of flying shrapnel and secondary debris looking to pierce flesh from the ground or walls nearby.
Other things to consider are bore life (too many rounds in a short time period gets the barrel too hot, later fluted barrel holds up better), supply situation, number of targets.
 
Ive seen vision of ASLAV-25 gunners engaging the bad guys....its exactly the same procedure as you describe. targetting information passed by the commander to the gunner, with the gunner also having a night vision or image enhancement aid (not sure what the commander is using, but targetting equipment is pretty sophisticated by the look of it).

The standard procedure for our Armoured Cav guys is to fire a three round burst and observe. Either the gunner or the commander can use follow up burst if there is any residual movement of the target.

The vision Ive seen is using the image enhancer, and engaging three or four targets simualtaneoulsy at night. The targets are dispersed at the beginning of the sequence, and are seen scurrying for a while, but these guns appear deadly, and deadly accurate. i would not like to be on the receiving end of these boys. The 25mm has no difficulty in achieving 1st burst kills for multiple targets. I dont know the engagement range, but it looks like it was at least 800m.

ASLAVs in the Australian Army are not generally used in the APC role though they can. They do however undertake recon and fire support for the grunts on the ground. The army is very pleased with their performance. Our principal APC remains the locally produced Bushmaster (not the gun, the vehicle), but our infantry does not use these vehicles as battlefield transport. They disembark outside the combat zone if possible, though there have been incidents in Afghanistan and iraq where they have been in the middle of a battle. They are better than a humvee, being resistant to IEDs and small arms, but an RPG will tear a hole in them.
 
How much HE filler in a modern 25mm shell vs how much HE filler in a modern Rh202 20mm shell? The 20mm shell HE content gets multiplied by 5 (i.e. 5 x ROF) giving us a rough idea how much HE each cannon can place on infantry or other soft targets.
 
20mm gun was very reliable and had long barrel life > 20,000 rounds....The best competitors got 8-10,000 rounds.
German doctrine was to run armored infantry independant of panzer units and the vast majority of the targets on the modern battlefield were troop soft targets or light armoured.

Re Pz 38t when the Pz II was upgraded to 30mm frontal armor the Pz 38t went up to 50mm. Their are instances where the Pz 38t took on KV tanks and beat them. Don't recall any such incident with Pz-II.

Personnally if I was running German rearmament in the 1930s I would have licence produced Pz-35t and then 38t instead of the Pz I II III IV. Meanwhile I would redesign the the Pz-III IV into a single model [with optional armament [infantry gun or PAK] for mass production to begine when war began.

Once Pz IV3 production begins the Pz 35t would be delegated to recon role and mass conversion to a SP gun [75mm IG in open mounts] for the Motorized infantry Divisions, while Pz units would be mix of Pz-38t with growing number of PzIV3. After a year or two the entire Pz 35/38 inventory could be converted en mass to mount French 75mm guns /later the Pak40 or captured Russian 76mm guns [AkA Marder] to suppliment Motorized infantry divisions and fill out PzJagger battalions. Later this same light tank industry could be utilized to build Marders or Grille SiG 15cm guns and ultimatly the Hetzer assault gun and follow on Waffentragger role, which would be taken over by the Zg tractor production [~ 17,000 per year].
 
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The best role for the MK-101/103 would've been as the main armament of some kind of SP AAA vehicle, IMO. So let's redesign the Pz-II in order to have the 3cm Flak on-board - a half scale Moebelwagen?
 
best role for the MK-101/103 would've been as the main armament of some kind of SP AAA vehicle
Click to expand...
That's what they did during 1945. The Heer designed a new 3cm twin flak turret which could be mounted on a wide variety of vehicle chassis.
Achtung Panzer! - Prototypes !
kugeltur.jpg


The German Navy designed a streamlined twin flak turret for the Type XXI submarine. Each boat had two such flak turrets. Early production boats had 2cm weapons in the turrets but they were designed for a variant of the 3cm cannon.

On the same subject.
The late war 3.7cm Flak43 was essentially a larger version of the 3cm Mk103 cannon. It may have been the best medium flak weapon produced by anyone during the WWII. I've never read of it being employed in the AT role. However with APCR rounds it probably had some potential vs armored targets.

3cm Mk103 Cannon.
420 rpm.
.330kg Projectile weight.
960 mps AP projectile velocity.

3.7cm Flak 43.
250 rpm
.685kg AP projectile weight.
790 mps AP projectile velocity.
.....Velocity is lower but projectile weighs twice as much. Not sure how that works out in terms of energy.
 
That would not work on a Pz II chassie. Too big Flak gun. Best I saw was a single flak on a Marder chassie. Besides there were more important roles to fill than SP flak . The Sdkfz SPW-251 could be adapted to fill such a role. Pz-38t was however very valuable as a "Grille" for the 150mm Infantry gun.
 
By 1945 it was a moot point as the 10 ton Pz II chassis was out of production. For that matter so was the 10 ton Pz38(t) chassis. However I think they were planning to mount a twin 3cm turret on the new 15 ton Hetzer chassis.

The 8 ton Spw-251 half track was probably too small for a twin 3cm turret. However they made a variant with a triple MG151 mount. Not a long range weapon but the sdkfz251/21 could certainly put out a lot of rounds. The gun crew looks well protected too compared to many early war flak mounts.
sdkfz251-21.jpg
 
davebender said:
3cm Mk103 Cannon.
420 rpm.
.330kg Projectile weight.
960 mps AP projectile velocity.

3.7cm Flak 43.
250 rpm
.685kg AP projectile weight.
790 mps AP projectile velocity.
.....Velocity is lower but projectile weighs twice as much. Not sure how that works out in terms of energy.
Click to expand...

Do try comparing like to like.

The standard AP rounds for the MK 101/103 had weights of 550 and 455 grams with velocities of 690mps and 760 mps. MK 103 may be down slightly. the 335 gram AP projectile was the tungsten cored one.
The tungsten cored shot for the 3.7cm Flak 43 weighed 405 grams and had a MV of 1040mps. This projectile did not have the streamline shape of the 30mm round and would have lost velocity much quicker however.
 
davebender said:
That's what they did during 1945. The Heer designed a new 3cm twin flak turret which could be mounted on a wide variety of vehicle chassis.
Click to expand...

Hold your horses :)
I've never said: "let's make a two-gun turret and mount it to a 20-ton chassis", but: "let's mount the gun on the 10 ton chassis, akin to Moebelwagen". So, a single cannon, mounted on Pz-II. Very much feasible in 1942.
 
Heer light flak spent more time firing at ground targets then at aircraft. A flakviering or triple MG151 mount was more useful then a single 30mm cannon for chewing up enemy infantry while still providing decent AA protection.

WWII Germany was out muscled in GDP compared to the Allies so it was important to get the most bang for the buck. That's why so many weapons such as the Me-109 fighter and MG-42 machinegun were less expensive then Allied counterparts. The Panzer II was cheap but a Spw-251 was even cheaper and the half track could adequately perform the moble light flak mission.
 
A Flakvierling requires more crew (eight men for towed variety) to operate, than a belt-fed 3cm weapon, while it provides just half of the useful range vs. aerial targets. 3cm has useful range as good as 3,7cm (circa 3km). The 20-round boxes (for 20mm) cut practical rate down at 40% of the cyclic - not issue for belt fed weapon. Flakvierling required 20 ton chassis, out of question for dirt cheap ;) Pz-II. Of course, why not mount the 3cm at SdKfz-251?
Forgot to say, with 3cm you have some chance to pierce some armor, compared with what 2cm was able.
 
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davebender said:
By 1945 it was a moot point as the 10 ton Pz II chassis was out of production. For that matter so was the 10 ton Pz38(t) chassis. However I think they were planning to mount a twin 3cm turret on the new 15 ton Hetzer chassis.

The 8 ton Spw-251 half track was probably too small for a twin 3cm turret. However they made a variant with a triple MG151 mount. Not a long range weapon but the sdkfz251/21 could certainly put out a lot of rounds. The gun crew looks well protected too compared to many early war flak mounts.
View attachment 180048
Click to expand...

Yes thats what I'm talking about. By 1945 all light chassie production had been switched over to the Hetzer chassie and the Waffentragger.SP flak would be low on the list of priorities for the Heer. As it was about 1500 Zg 3/4 track were utilized to mount flak guns up to 37mm flak.
 
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During 1942 RLM issued an advanced specification for a 20mm cannon. 1,000 rpm and 1,000 m/s projectile velocity. The MG213 revolver cannon won the competition and was almost production ready when WWII ended.

However it wasn't the only weapon in the competition. There was a conventional gas operated autocannon designated "MG301". Does anyone have additional information on this weapon?
 
There's a cultural perspective being missed here. Germans don't consider the 20mm a cannon calibre. Anything under 30mm is a machine gun calibre to them. So it's the largest machine gun calibre with the best all round performance compromise between smaller/larger calibres in many specified roles. Just like the .50 cal is for the Americans.

The 2cm machinengewehr round is to the germans exactly what the .50 cal machinegun round was to Americans and the .303 to the British. Reliable, quantifiable performance.

That said 3cm or larger was preferred for FlaK, the Mk101 you're talking about, similar but slightly higher charge weight and muzzle velocity, more recoil, comes in both percussion and electrical ammo (percussion ones were used in Romania).
Thing was Luftwaffe security forces formed the centralised FlaK formations in Germany and at forward airfields so got preference, they got all the 3.7cm SPG/AAA whilst Army got all the 2cm.

It was just the way it worked out, check out the OOB by unit and you see army with 2cm FlaK and luftwaffe FlaK with 3.7cm, both have 8.8cm. This also suggests that around command posts ground attackers will face 2cm point defence, near airfields it will be 3cm as a general rule, you can find targets by what is shooting at you.

I realise what I said is confusing, Tony Williams iirc told me about Mk101 based FlaK used around Romania, and LW got the lions share of 3.7cm.
 
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Hi Vanir

havent seen you aropund that much, but perhaps youve just been lucky we havent crossed paths lately..... good to hear from you anyway.
 
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