thank you, now it starts to make sense again. must say that I never found a original source for the "50 mm" and it was only hearsay. the Husqvarna catalog dont mention anything about the brass lenght. I never see swedish brass ,only german made cases and one time Rauhfoss brass from norway.
Husqvarna must have sold a roundball mould with the rifle and someone in sweden must have importet german made 65 mm long brass and cut it to 46mm.

if your rolling block is also chambered for the 46mm long brass and my own M 17 A is having much more a 46 mm long chamber than a 50 mm I would assume that the original length was indeed 46 mm. when you load a roundball its clever to use a 46mm instead a 40 mm case for the cats head bullet.