Could you two link to your sources so we can see them? A quick google's giving me the same muzzle velocity (790 m/s) and near-identical penetration properties, but I don't think I could stand the mockery if I cited Wikipedia as a source here.
Also, physics nitpick, speed's not acceleration. You're talking momentum, mass * velocity, if you're talking about mph and mass. I'll leave the wisdom of discussing gun performance in terms of momentum to the crowd, though.
No problemo
Here we see a comparison of the MV of the Pak 40 and KwK 40. For those of who who do not know, 2,300 fps is about 700m/s and 2,600 is 790m/s. This is important to realize, because in game, units like the Marder 1 and Pak 40 AT gun (both of which, obviously use the Pak 40) do indeed have 1,200m range because of this far higher muzzle velocity. In contrast, guns with the KwK 40 (Panzer IV, for example) only have 1,000m range, but still benefit from its tremendous accuracy in game. The reason they do not have 1,200m range is because of the fact they fire projectiles at a much slower velocity. For comparison, we see the M1 76.2mm's performance and MV here...
2,600 fps again, like the Pak 40, AKA ~790m/s (not to mention being half a pound heavier than the PzGr 39), and significantly faster than the KwK 40. This is why the 76.2mm guns, and the Pak 40 should have 1,200m range, but the KwK 40 not. Furthermore, we need to be incredibly judicious about which units we hand out 1,200m range, as otherwise we encounter a scenario of power-creep where a unit must have 1,200m range to be useful, rather than having it as a unique advantage. In fact, in many ways I think we have already gone a bit too far with it and should probably either scale back the amount of units with 1,200m range, or decrease their accuracy at such range to give a greater role for the 1,000m units. As for the Panzer IV, I already said that it is well-deserving of a CP buff, along the -10 or so CP line. Give it the M4A3 75mm treatment and hopefully we will see more of them on the battlefield as a bread-and-butter tank that it always was and should become in game.
1. the pzgr 39 could penetrate more armor than the m62
2. the projectile was not much slower than the m62, Much closer to the 76mm than the 75mm
1. That is because the M62 packed a far larger charge of HE filler than did the PzGr 39, as was intended to have a far greater after-armor effect. Thus, this is comparing apples to oranges in the same way that it would not be right of me to compare the M79 shot (AP-T) to the PzGr 39 (most definitely not AP-T) and using it as a reason to lobby for even more AP on the M1 76.2mm's behalf, as it defeated more RHA than did the PzGr 39. The difference is, crews utilizing the M1 76.2mm had the option to switch between the M79 shot and M62 at will and en mass, where as the KwK 40 rarely had such a luxury.
2. The M3 75mm is not lobbying for 1,200m range though, and you utterly failed to address my point. The Pak 40 and M1 76.2mm have sufficient velocity (combined with ample weight) to be a 1,200m range weapon, the KwK 40 does not. Keep in mind 1,200m range also features a variety of weapons with higher velocity than either of these guns, such as the KwK 42 8.8cm or the M7 3-Inch. The M1 76.2mm and Pak 40 are at the threshold of 1,000-1,200m range, and the fact is they had enough to differentiate themselves from the slower KwK 40 to warrant such range.