I have the Hasegawa 1/72 scale Karl Morser that I'm about to get started on. Hasegawa based their kit on the prototype vehicle, with 8 road wheels per side; the production vehicles, all 6 of them, had a different road wheel arrangement with 11 road wheels per side. Does anyone know if the prototype was used in action as well, or did it spend the war at the proving grounds at Paederborn collecting rust? Two vehicles on their way to bombard Paris were captured by the Americans after their trains were shot up by allied fighter-bombers. At least one of these guns was brought back to Aberdeen proving grounds after the war, only to be cut up for scrap along with 2 K5(E) 280mm rail guns sometime in the 50's or early 60's. The Russians have 1 gun at their armor museum at Kubinka, but information seems to be very thin on the ground, or non-existant about the fate of the other 4 production guns and the prototype.
I emailed Hasegawa for compressed running gear that was not included in the kit, and they sent it right out to me, no problems! Thank you Hasegawa!
Now if you would only break out one of those old molds and make the production versions with the modified running gear and the later, longer ranged 540mm mortar assemblies that were fitted beginning in 1943

Does anyone out there make the late war 37mm Flak 43 dopple lafette in 1/72 along with their limbers and ammo trailers or half-track mounted? Each of the Karl heavy mortars had 2 of these twin guns in their TO&E for close in Flak protection