The first iteration, the HL (4.5 kg), has a blunt nose. The HL/X (HL/A 4.4Kg, HL/B 4.75Kg, HL/C 4.8Kg) all have an aerodynamic 'cap', and for most purposes, they are basically the same with a weight difference (which seems to have been factored in the propellant weights) and the same velocities. In fact, most weapons of the 75mm-76.2mm that the Germans manufactured a HEAT round for have a velocity of 450 m/s. The infantry guns were less , I believe. The 88mm had a 600 m/s, so I suppose the fusing would work at that velocity.
They all have one bad physical characteristic, that is they all have a axial center of mass (COM) WAY towards the rear. I would estimate it to be as far back as slightly forward of the driving band. The HL/C would have the COM a little forward than the A and B, but not much. Take a water bottle and fill it with an inch of water (standing up in freezer) and freeze it, now try and throw it in a spiral (ice facing the rear),. Something like the HE round would even be much better as far as having a COM towards the middle of the round.
The 'training' numbers, I presume, mean a known range and a zeroed weapon. The Panzerworld page regarding tank combat firing methods have these recommendations:
The above facts point to begin training anti-tank gunners and tank gunners in artillery firing methods. The key differences for the above-mentioned anti-tank gunners and tank gunners are:
The gunner always uses the same aiming point.
The commander provides range commands, also against moving targets, and determines the range to the target from the impact.
In regards to very flat trajectories, it is sufficient to make aiming marks at 200 meter intervals for the anti-tank gun and tank gun. Minor corrections can then be made in the usual manner by changing the aiming point.
At short distances, with sufficiently flat trajectories and large target areas, the firing method can be kept, i.e., with the approximated or measured distance being corrected by adjusting the target to the target width or height.
The task now is to find the border between the two methods, which differ according to ballistics and ammunition.
In regards to the 200 meter marks, it appears appropriate that the limit whereby raising or lowering the flight path along the height of the tank (on average two meters) gives a change in distance of less than 200 meters. This is approximately the same range at which the target area change by less than 200 meters, e.g:
Shot Maximum range
7,5 cm Pak/KwK 40
Pzgr. 39 1200 m (~95%)
Pzgr. 40 1400 m (~70%)
Gr. 38 Hl/B 600 m (~97%)
kwk 37 Accuracy Training only
Round Range
100 m 500 m 1000 m 1500 m
K Gr rot Pz 100% 100% 98% 74%
Gr 38 Hl 100% 100% 92% 61%
kwk 40 Accuracy Training only
Accuracy Training only
Round Range
100 m 500 m 1000 m 1500 m
Pzgr 39 100% 100% 99% 77%
Pzgr 40 100% 100% 95% 66%
Gr 38 Hl/C 100% 100% 85% 42%
The L24 gun has to accelerate the round in a shorter period of time than the L48, not only that it also gets 'spun-up' quicker. In other words, it is pulling more Gs to get it out of the barrel. Comparing the HL to the HL/C, the HL/C weighs more. looking at the L24 training accuracy, there is very little difference in the accuracy at 1000 meters. 98% vs. 92% and the K Gr rot weighs 6.8 Kg vs. 4.5 Kg? It just strikes me as odd that the 1000m accuracy is better with the L24 than the L48 (maybe L43). Also, the Germans recommend a 600 meter range as a SOP. I get that you are using the Germans numbers, but it just doesn't square with that report (the Germans were more than likely using HL/B in many weapons in Sep 43). The Pak 40, for example, only 'started' with the HL/B.
Hmmmmm. To be continued.
Edit: Just an interesting note is that I do not see 'training' ammunition (Ub) as far as HEAT for many of these weapons. Also, the AP/HE/HEAT weights are different but I suppose the German sights just used the closest matching velocity in many cases.