It looks like the trajectory of in-game DM43 matches the time shown on the table pretty closely. This was my attempt to replicate the outermost curve, T = 1.24s
Below you see my test with Marder 1A3, shooting DM43 at one of the test drive tanks, distance 1050m.
I measured the time to target in Davinci Resolve, and got ~1.19 seconds. Please take the number with a grain of salt, this is not the most precise testing method.
Found more documents, here is the source
Most interesting is this table showing penetration at different angles, at 100m and 800m distance. This projectile is not named as “DM43” but the schematics and description match it exactly.
This graph is a biiig doozy.
At first, I thought it might show the performance of an alternative shell design with the core made from plain hardened steel, but this level of performance is far above what a 34g 12.7mm projectile could achieve. Especially one without a penetrating cap.
Next, a full caliber 20mm 111g projectile. It’s not as far fetched, as it might be able to theoretically defeat both a 30mm/27.5° at ~810m/s and a 45mm/30° target ~1135m/s, provided that the plate is fairly soft enough so the projectile wont shatter. But this is unrealistic as well.
Finally, I’ve settled on explanation that this test was simply carried out against a very high hardness armour.
Here are the result of the soviets testing german projectiles against medium 30 and 75mm plates and against 45mm high hardness RHA.
If we take the data point of the 37mm APCR against 45mm/30° as 890m/s, the DeMarre estimated BL for the DM43 against 30mm/30° is 820m/s, very close to what we see in the document.
I find it interesting how similar Pzgr.40 and DM43 are.
Good day, here’s another document courtesy of @Conraire on the M114 thread (sorry to ping you so much!)
This is for M139 20mm cannon, which is chambered for the same 20x139mm as RH-202 meaning they share ammunition. The XM601 API-T is the US designation for DM43. 
Notice the API-T penetration below stated as 1 & 1/4 inches steel at 1000m. That is 31.75mm, and matches the other sources posted here previously.
Here is the russian source giving the same number
Thats cool to see.
Overall while im not the best with post WW2 stuff, im planning to widen my info topic from WW2 to WW1, inter war and to modern-ish.
Like this one and the other 2. Where these sources will come quite handy.
True, DM43 may be a post-war development but the fundamentals are still the same!
Just looking at the schematics you see how similar they are.
The casing they are fired from are also similar, 20x138mm compared to 20x139mm
So I wouldn’t be surprised if they performed roughly the same, and that the “64mm at 10m” we used to have in game is in fact the real performance of 2cm PzGr 40
yeah, i had the same thoughts. I mean the 20x138mmB Rheinmetall Pzgr.40 only has 4g less propellant with 49,04g to 53g of the 20x139mm.
the core is of 12mm instead of 12,7mm. The Pzgr.40 had like 3-5 generations (with also a 13mm core) and different lengths with different weight from 100g to 106g. So aside the construction similarity also similar weight to 111g.
Do you happen to have any tables for 20mm Pzgr40?
I made comparison cards to show in-game performance (left), and what we know from sources (right)
20x139 DM63:
20x139 DM43:
(100m & 800m sourced from Rheinmetall table, 1000m from Russian table)
Nope sry. I only know by the Panzerbeschusstafel that it can penetrate the 45mm side armor at 30° of a T-34 from 100m, which would be 1mm better than the 44mm/30°/100m of the DM43
(Or technically more than 45mm/30°/100m, because it can penetrate that cleanly and its not its limit.)
If you look at the chart in my previous post, it also shows the results of testing the 28/20mm German atr against 45mm of soviet high hardness RHA.
It penetrated 45mm/30° only above ~1100m/s, which is above mv of the 2cm Pzgr. 40
What do you think of the comparison table I posted, and how does it match up with your simulations?
Looks like your old graph (think you called it “third estimate”) over performs at close range. It is correct at 1000m though.
I didn’t realize at first, but since this graph tells us the velocity of projectile at two separate distance points, we can compute it’s external ballistics!
The projectile is highly aerodynamic and has a relatively low drag for it’s caliber.
Now there is a problem: the muzzle velocity for this projectile is stated to be 1100m/s, but if you extrapolate the 1135m/s at 100m data point you get the muzzle velocity of 1187m/s.
If we assume the mv. of 1100m/s, the striking velocity at 800m is now only 741m/s.
| Range (m) | (m/s) |
|---|---|
| 0 | 1100 |
| 100 | 1050 |
| 200 | 1002 |
| 300 | 955 |
| 400 | 910 |
| 500 | 866 |
| 600 | 823 |
| 700 | 781 |
| 800 | 741 |
| 900 | 702 |
| 1000 | 665 |
| 1100 | 628 |
| 1200 | 593 |
| 1300 | 559 |
| 1400 | 526 |
| 1500 | 495 |
I’ve updated the graph.
Then maybe its with Pzgr.40 and the other core?
Idk, thats simply what the Panzerbeschuß Tafel der 2 cm KwK 30 u. 38 shows.
The difference in penetration between two cores is small, since its bigger diameter is partially compensating for a bigger mass. It’s ballistic limit only ~20m/s less, this wouldn’t drastically change it’s performance.
Soviet high hardness armour is more resistant to small caliber/subcaliber projectiles, that’s all there is to it. I sincerely doubt that the germans went to the trouble of procuring, testing armor plate from soviet tanks and changing this specific penetration value to reflect that. They most likely simply used the data they had (obtained against their own armor) in the manual.
I stand by my predictions. We don’t know for sure why (what seem to be) test values from this german document deviate so much from the results of my model. But I know that it has worked extremely well for predicting penetration performance of myriad of other subcaliber shells, and therefore, it’s actually more (not less) trustworthy than a single historical document stating otherwise.
As far as I remember, Gaijin just equalized the penetration values for similar autocannon rounds across the board. I think they treat them as a class, ie. AP 20mm, AP 30mm, APDS 20mm, APDS 30mm, regardless of nation and manufacturing differences.
Nice work!
I don’t know if it’s any help, but here’s the velocity table for DM48A1 Practice-Tracer and/or DM51A1 HEI-T. I’m trying to find one specifically for DM43, but no luck so far.
