I have a pair of 51's that are great for me.
Pic from a couple weeks ago. 12ga 2.5" chambers.
7/8 oz #6 ITX or 1 ox #5 Bismuth is quite effective if you let them get close enough.
Most Husqvarnas will have 2.5" chambers. I think the best ones are the ones with a Greener crossbolt. I can't think of the model numbers right now. Model 20's are utilitarian but quite stout, they are hammer guns with under lever lock up.
Like said before many models and grades. Mostly 12ga short chambers.