a husqvarna catalog for sale in sweden showing the hussvarna model 17 a combination gun with 20, 24 or 28 rifle barrels. while I know one of the pages never see when they were offered. thought by myself mabye up to 1914 but this catalog is printed in 1931!
https://www.tradera.com/de/item/301784/538225006/husqvarna-skjutvapen-katalog-

they offer loaded rounds in 20, 24 and 28 ga., brass cases, primer and roundballs