I think you mean the cast in the middle here. this was cast in a very light sxs combination gun with a 24/40 barrel from Funk in Suhl. the bullet itself was sitting very deep into the case and the combo was intended to shot a light load, no doubt.

the only load advise we(Fuhrmann) ever found was this here: 21,9 gramm cat head bullet over 2,5 gramm black powder.

this was for another style of hunting when wounded game was chase with hounds and killed in the end with the Hirschfänger. the bullet itself is a very light one here because the RWS catalog shows 33,3 gramm for the 24 ga bullet and 39,4 gramm for the 20 ga bullet.

the bad news about your chamber cast is that another rule fall's.