It certainly is stronger than the model 17's and 20's which used the Lefaucheux-type underlever action.

I have a 17, I guess it is.

Seems to me I read a Husky descripto some time ago, explaining the straight rifled would shoot shot fairly well, but also ball form a brass case with a black powder charge. The requirement was that a moose gun had to have rifling. The straight rifling satisfied that law but at fairly close range, shot ball accurately enough. Mine does.

Some guns have smooth one side and rifled the other- as-is the one I have, with a 13 bore (.705") straight rifled for brass case, and 16 bore modified choke for a thicker paper case with shot. The chambers are identical, but the bores on my gun are .031" different.

A gun like this one, perhaps the same gun was discussed on a different, (Swedish rifle) forum, saying the straight rifled barrel was chambered for a 2 1/2" brass case while the spiral rifled tube was chambered for a 2" brass case - both bore black powder and ball, with shot as well for the staight rifled one.