ran so many- primarily Jewish- scientists out before the war began: they were able to build crap like this
as it was; if they'd had the foresight to keep those researchers in Germany, or grabbed them from other countries before they could escape to Britain or here...
This thing had a 800mm- 31.5"- bore, fired a 5.25 ton HE or 8.25 ton AP shell up to 29 miles for the HE, 23 for the AP, muzzle velocity around 2700fps. Damn.
The good thing about this? Hitler & Co. had people and other resources tied up with crap like this instead of working on other things. As was they developed the first tv-guided bomb and a lot of other things, so any oversized time-consumer like this was a Good Thing for us.