German 20mm guns

[Olle Petersson]

Hi again all! Here's a topic for the Grogs.

About two months ago someone asked if there's a difference between the German 20mm guns in the game.

I've just searched for that thread, but the search engine is too slow as usual...

I recall it went something like:

- One person replied "no, they're the same".

- I replied something like "the FlaK gun has longer barrel, and possibly higher ROF".

- Another replier noted that in the game (CMBO) all German 20mm guns are listed as having the same muzzle velocity and ROF.

Since then I've been on a quest to find out the truth, and now I've managed to put bits and pieces together to this:

<UL TYPE=SQUARE><LI>During WW2 there were two basic German 20mm gun designs; model 30 and model 38. Model 30 was a pre-war production model in ample supply by 1939. From around 1939 and on all guns produced were model 38, so near the end of the war (at the time of CMBO) practically all guns in use were model 38.<LI>The major difference between model 30 and model 38 was the cyclic ROF, that was somewhat higher in model 38.<LI>All 20mm guns used the same ammo, namely the Italian designed 20x127 also used for Solothurn ATRs.<LI>Both gun models were available in two versions; KwK and FlaK. These versions differed in barrel length (KwK 110cm, FlaK 225cm) and mounting. The KwK was fed from a 15 round clip, and I haven't found anything suggesting that the FlaK was any different.

This means that KwK30 and KwK38 were fully interchangeable, while KwK38 and FlaK38 were not.

Now, how does this apply to CM?* Since they all used the same ammo, there should be a difference in muzzle velocity between the KwK38 and FlaK38, as is not currently appearent. This difference, however, would then only have some minor impact on accuracy and armour penetration.

* Next step is to determine which of the 20mm guns in the game are FlaK and which are KwK:

- Obviously all dedicated AA guns are of the FlaK version; the towed single 20mm, the towed quad, the SdKfz 7/1 and the Wirbelwind.

- What other 20mm guns are there?

The vehicle mounted 20mm guns in PzKw IIL (Lynx), SPW 234/1 and SPW 250/9.

The generic source I have say that all three used the KwK.

Let's take a closer look at them one at a time.

SPW 234/1

One, more detailed, source confirm that the KwK38 was standard, but mention that "Very few SdKfz. 234/1 were rearmed with a 20mm Flak 38 L/112.5. They were known as Schwerer Panzerspähwagen (2cm Flak 38) - Schwebelafette". This suggests that the SPW 234/1 in CMBO should have a KwK38, since it's supposed to be the common version and not one of the "very few".

Steve has mentioned that the SPW 234/1 in CMBO can elevate it's gun about 70 degrees, which makes perfect sense for those fitted with FlaK38 because of the special mounting. If the common KwK version of SPW 234/1 also had this feature I don't know, but I suspect not.

My best guess is that the SPW 234/1 available in CM as it is depict one of those very few with FlaK38.

PzKw IIL

I've so far found nothing to suggest other than that all versions of PzKw II had a KwK gun. This is further implied by the fact that it can't attack aircraft in CMBO.

SPW 250/9

As noted above; my generic source suggests KwK. In CMBO it can attack aircraft. This could be a confusion, in line with the SPW 234/1 mentioned above, but I have nothing to support that suspicion of mine.

Comments are welcome!

Cheers

Olle

[ 08-12-2001: Message edited by: Olle Petersson ]

[Olle Petersson]

Ooops! Not a single reply in 24 hrs. :confused:

I thought this would generate at least some interest...

Cheers

Olle

[Subvet]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Olle Petersson:

Ooops! Not a single reply in 24 hrs. :confused:

I thought this would generate at least some interest...

Cheers

Olle<HR></BLOCKQUOTE>

Well, thanks for the post. It isn't that I'm not interested or not appreciative of your research, I just didn't have anything to add to it. So don't take the lack of response to mean we didn't care at all.

[MikeyD]

I'm reminded of the classic desert war memoir "Brazen Chariots" (by Crisp?) how the commander of a new Stuart 'Honey' is fired on by a 20mm-armed PzII. He said it was the only time he was actually able to see a round in flight. A small black dot acrhing toward him, only to fall short. His 37mm gun then dispatched the unfortunate PzII. The Stuart's 37mm was apparently in an entirely different class than the 20mm guns on German light armor.

[Panzer Leader]

Thanks, I love the 20mm, both (or all 4?) types. I often get PzIIL's and 234/1s and just love'em! And on the defense, nothing is better than a batery of 20mm flak guns to hold the capitalist dogs at bay!

[Sledge59]

Thanks for sharing your research Olle, very informative. Looks like you must have the definitive information on this subject or the grogs would be in a frenzy.

[Olle Petersson]

Here's a little more on why I think this is interesting for CMBO (as well as a weekend bump for those who doesn't check this website on weekdays):

As noted before, the in-game effects are merely a matter of AA capability or not. Not a big deal...

It's the academic approach that's more important:

* BTS has stated that they want the game to be as realistic as possible, and they've managed to get a long way towards that goal, especially when it comes to the hard data on vehicles and units.

* It's highly probable that CM will be used as reference material by some gamers who have no other source easily accessible, as is currently the matter of that board game (you know which I mean) that most gamers know contain some inaccurate information but still use for reference.

* Based on the two points above, it's desireable both to BTS and to CM players that the data presented in CM is as accurate as possible. Some sort of official clarification, possibly in the shape of an online errata and extension to the manual, from BTS would be nice.

Desired clarifications:

* Why all 20mm guns have the same muzzle velocity in the game, and which that really should have some different MV. As noted I think the given data is for FlaK38, while some vehicles should have a KwK38 with lower MV.

* If the modeled SPW 234/1 actually is one of a few SPW 234/1 Schwebelafette instead of the regular version. (And a similar note on SPW 250/9.)

Cheers

Olle

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Olle Petersson:

...This suggests that the SPW 234/1 in CMBO should have a KwK38, since it's supposed to be the common version and not one of the "very few".

Steve has mentioned that the SPW 234/1 in CMBO can elevate it's gun about 70 degrees, which makes perfect sense for those fitted with FlaK38 because of the special mounting. If the common KwK version of SPW 234/1 also had this feature I don't know, but I suspect not.

My best guess is that the SPW 234/1 available in CM as it is depict one of those very few with FlaK38.

<HR></BLOCKQUOTE>

von Senger und Etterlin lists the sPz Spw Sd Kfz 234/1 as having the 2 cm KwK 38 with elevations +75º to -0º. That compares favourably with CM's model.

[GenSplatton]

<BLOCKQUOTE>quote:</font><HR> * Based on the two points above, it's desireable both to BTS and to CM players that the data presented in CM is as accurate as possible. Some sort of official clarification, possibly in the shape of an online errata and extension to the manual, from BTS would be nice.

<HR></BLOCKQUOTE>

I think the time is better spent finishing up CM2 myself. Personally, I can live with a few small errors in the game. I think anyone who would use a game as a sole source of gunnery data is probably a little off base. If they are prefessional historians, I'm thinking they should be doing a little more research than trusting the muzzle velocity listed in CM. If they aren't professional's, then they can be wrong on occassion, it's good for the soul.

[Wolfe]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Olle Petersson:

* Why all 20mm guns have the same muzzle velocity in the game, and which that really should have some different MV. As noted I think the given data is for FlaK38, while some vehicles should have a KwK38 with lower MV.<HR></BLOCKQUOTE>

Actually I think the data may be for the KwK version. Hogg's 20th Century Artillery, Bishop's Encyclopedia, and the Handbook on German Military Forces all give the muzzle velocity for the FlaK38 as 900m/s. In the game it's 780m/s. Though the Handbook does list the MV for different shells: 2950ft/s (900m/s) for HE, 3250ft/s (990m/s) for AP40, and 2625ft/s (800m/s; which is close to the 780 listed in CM) for AP. But I still think the 780m/s listed in CM is for the KwK gun.

Also, Intro to Weapons Data lists the "L/50" version of the gun with a 780m/s MV.

Hopefully this'll be looked at for CM2. The PzIC had the KwK30 and various PzII tanks had either the KwK30 or KwK38. So the difference in ROF between those two guns will also be an important distinction in CM2.

BTW, were some of the PzII models that started out with the KwK30 "upgunned" with the KwK38 without changing the tank's model number?

- Chris

[ 08-19-2001: Message edited by: Wolfe ]

[Tripps]

<BLOCKQUOTE>quote:</font><HR>Originally posted by GenSplatton:

I think the time is better spent finishing up CM2 myself. Personally, I can live with a few small errors in the game.

<HR></BLOCKQUOTE>

i concur, but i like the fact BTS didnt screw everyone over like other game manufacturers by sending out half finished games and then making people wait for the update to fix it all, (not that CM is buggy, i too, can live with small errors if thats what they are) what is being discussed here is not a major change is it?? it should be a pretty easy job to change muzzle velocities and stuff, admittidly, after conclusive research is done (no slight at you Olle! )

so, while they are no doubt researching for CM2, they could maybe add the 20mm to the drawing board...

[ 08-20-2001: Message edited by: Tripps ]