Development questions, please respond.

[Marcello]

OK, let's me get this straight: are the germans going to develop and field FOUR (105/128/150/175mm) tank guns in parallel?
That's a massive waste of effort and a logistical nightmare. If some uber AFV is needed for the propaganda newsreels you can always stick an artillery or naval gun on it. But for actual tanks, TD and Stug you should cut it down to no more than two pieces (you might need something lighter for armored cars and such but I am speaking about guns in this class) at any given time.

[thatguy96]

Well honestly, Hitler wasn't exactly known for making logistically conscious decisions, and the German Army from day one was a logistical nightmare because it had to make ends meet on equipment. Depending on SGTGunn's alternate history, Hitler might still take responsibility for all armament development decisions at a certain point (as he did in real life), which might lead to this situation.

Remember, Hitler was the guy who with limited resources decided to produce two initial production runs of tanks, one of which would become the Tiger, and other of which they had to find a use for. The decision to create the Ferdinand/Elephant was not one that had been preplanned for the excess, it was done because they needed to make use of them.

[Marcello]

"Remember, Hitler was the guy who with limited resources decided to produce two initial production runs of tanks, one of which would become the Tiger, and other of which they had to find a use for."

Well the usual story was that it was a Porsche decision, as the guy felt that he had already won and thus decided to start production in advance. Hitler liked Porsche design but actually listened to the informed opinion that it was unsuitable for mass production. Besides RecruitMonty is posting data for the 90's and Hitler would not be around anymore.

[PlasmaKrab]

Guys, are we still talking about the "Das Reich" mod? If so, and assuming I have understood anything to the storyline, there would be no Hitler to heed the Imperial decisions and ruin the whole business in a few years, right?
This and the rest being considered, I agree with Marcello that four parallel tank gun calibers are overcomplicated. Now how about using them as two parallel runs, each one evolving over time from one caliber to another? Say, start with 105 and 150 as main weapons, respectively for light/medium tanks and light TDs and for heavy tanks/Stugs. Meanwhile, keep the 128 and 175 for seldom exceptionally heavy vehicles, and later on switch them to main calibers, while developing new ammo for them.

There again, I'm not sure there is much point in such large guns once you have better technology for AP rounds (make that the 60s, I don't know the technical development line you have in mind).

[pdoktar]

Is a tank with a 175mm gun feasible? It would weigh like 100 tons if it carried enough armour and ammo.

[Marcello]

"Is a tank with a 175mm gun feasible?"

More likely a Jagdtiger style vehicle. Feasible ? Probably yes. Sensible ? Absolutely no.

[Marek_Tucan]

Questionable whether such gigantomaniac designs would come to life under other than Hitler's (ie by default more rational) leadership... I'd rather envision tank main gun stopping at 105mm, later advancing to 120mm (or around- say US and Brits going for 120, Germans for 128, Russkies going 107mm->122mm->130mm), with this caliber reserved for heavy tanks, so... 1950's, med. tanks 88/90/85/20pdr, heavies 105/120/107, later medium 105, heavies 120/128/122/130... with maybe the German 15cm KwK coming to life but for exceptional use on some übertank with minimal practical employment or some SPG with a little bit better one
If you really don't want to leave the 175mm thing, I recommend you go for 17cm as that was caliber used in German artillery already. Also it would come with bonus - the 17cm field gun had practically same lavette as 21cm howitzer IIRC so your wunderpanzer may have two versions, one with HV gun and one with destructive howitzer.