Husqcvarna Model 17 a this here is described as a 24 ga double rifle
https://auctionet.com/de/4647424-husqvarna-modell-17-kal-24-bis-nr-82007

right barrel rifled - I believe for the swedish 50 mm long brass case and left barrel straight rifling than for the 2 1/2" = 65 mm case and roundball
nice little blackpowder toy