1920 Carbine, Less Forearm

[ithacaartist]

As I understand it, the front tang added to the frame was essential to the functioning of the carbine configuration, in that an extra recoil spring interacted with the tang to help get the massive weight of the barrel back into battery. This, in addition to carbine-specific ammo loaded with a bit of extra oomph to energize a cycle. In the pic posted above from Lugers at Random, someone has drawn in a couple of annotation arrows, each pointing to the now superfluous notched sight on the rear toggle link. This makes me think that the Luger in the pic was a standard configuration pistol with a carbine barrel clomped on. I'm aware that Stoeger re-barreled pistols to similar lengths, without the tang setup. The bottom, rear of the barrel in the book, however, looks like it does not have the slot cut to accommodate the tang, so I think it was one of the rebarreled-to-order guns addressed on the page. How did those manage to function--without the extra spring, etc.?