Well, the armor penetration depends on the hardness, so you can’t really give one specific armor penetration value. How would you know when you change from one plate hardness to the next?
At best it would be something linear. Like 100mm pen = 260 BHN, 101mm pen = 259 BHN.
But that’s kinda pointless.
In the end you want to know whether a shell is going to pen X armor of Y hardness and Z angle.
Like the T-34s armor is going to give wildly different results than a Shermans.
So at best the penetration formula can take those already known factors into account to calculate a more or less accurate result.
For example, the IS-2 HHA would be much more resistant to the APCR round, afaik.
So the penetration graph that takes that specific range of hardness into account, wouldn’t work for accurate estimations against the 100mm HHA.
The USA supplied pretty much all of the molybdenum in the world during the WW2 years, which meant we could substitute it for both tungsten and nickel in steel alloys no problem. We also had access to sizeable vanadium reserves, which had similar applications. Since our machine tooling and other alloys needed less tungsten, we were free to use it elsewhere. We also had access to all of Latin America’s tungsten reserves to import from, on top of the fact that we were also right behind Portugal in tungsten production. The only strategic resource the USA really struggled to procure in abundance was chromium, at least once we started the production of synthetic rubber.
DM63 uses a gen 2 APDS calculator in game. Which comes with better slope modifiers (divide the flat pen by the respective 60 deg pen, you get aroudn 2.62, which means 2nd generation).
However the penetration values shown match much more what would be expected from a gen 1 APDS design, that is, a sharp uncapped core of tungsten carbide, which makes sense.
So DM63 likely uses the wrong calculator in the first place.
If we consider this relationship accurate, then the BL at angle A will be equal to BL at 0° + 0.667*A^2.
For example: the estimated BL for the german 5cm APCR against 2.5in. (63,5mm) at 0° is 2182fps.
Same plate angled at 46° (Sherman UFP) will be perforated with striking velocity of, at least, 2182 + 0.667*(46)^2 = 3593fps, which is about 100m distance for 5cm L/60 gun.
As you can see there is a significant spread of results. After eliminating some of data points related on unrealistic situations (like the 5in. plate of 338 BHN) and others that deviated far too much from the average to be of use, it resulted in this data set.
Because in the data set there was no data on performance of these early tungsten carbide cores for velocities above approx. 3200fps, I’ve shown the extrapolated values with a dotted line.
Edit: As a side note, the german 5cm APCR is scary. If this game used it’s real life performance, the Pz.III’s would be 4.0 material, lol.
Interesting.
Tho where did you get 1135m/s for the Pzgr.40/1?
And by Russian, british and USA testing for the 40 it even got to 1200m/s, how would it then perform?
Like I said last time, ( I remember our previous conversation on this topic), the earlier 5cm Pzgr.40 (without a suffix) was lighter and had higher muzzle velocity, nominally 1180m/s, but could be anywhere between 1150-1200m/s, depending on the wear on the gun.
While the later one, Pzgr. 40/1, was heavier and had lower m.v., but better ballistics.
Thats not readable? And i dont see a 5 at the back?
Im not doubting the velocitys and i know of both 1180 and 1200, but i was more interested in the 1135 instead of 1130 from in game.
From the looks of it, the Pzgr. 40/1 would outperform the Pzgr. 39 at any range 🤔
But maybe I’m just imagining things.
In the ammo manual it says it should only be used till 800m.
Even though I feel like that German manuals generally underestimate the performance difference at range.
But I guess the difference isn’t big enough to be worthwhile.
Honestly I don’t remember anymore why exactly I use 1135m/s figure, it was just there in my external ballistic calculator. It might be because I once saw a figure of 3725fps (1135.38m/s) in some allied intelligence report on this gun, but I can’t find it now.
But these are really tiny details that are virtually negligible in the grand scheme of things. More importantly, I believe that this historical german FT is quite simply wrong.
The drag on this shell is simply too high, pretty much same as that on the “H”-type arrowhead design of the earlier shell. In the graph I posted earlier I’ve used external ballistics of M93 HVAP, since it has almost identical external shape to the 5cm Pzgr.40/1.
If we were to trust the german FT, the newer APCR shell would have lower penetration than the older one, up to 500m, and only a tiny advantage (5mm at most) at longer range. I don’t believe that germans would change it’s design just for this.
It would require the use of tungsten carbide, a rare strategic material.
Firing hypervelocity shells like these heavily accelerates the wear of the gun.
The 75mm gun would have a much better HE shell. Like, by a lot. The difference between 75mm and 88mm or even 105mm is much lower (percentage-wise) than between 50mm and 75mm HE.
