I can't speak to the Husqvarna and certainly I am ignorant of Swedish game laws. I have a pre-1891 proof law Jost & Diehl combination gun in 16 X 10.5 X 47R and the shotgun barrel has straight rifling. I knew such existed but this is still the only shotgun barrel I've seen with straight rifling. Anyway, it is choked a very tight full and, Axel told me the straight rifling in shotgun barrels was a fad that came and went. I assume he meant in Germany. That's all I THINK I know about them, obviously subject to correction.