Knowing the fact that Alaskan state trooper issue Brennekes for business, it would not be a stretch of reasoning that perhaps a Canadian dealer whom caters to law enforcement needs could/would import them into our borders.
I checked into what version Brennekes they use and it seems they rely on the 2&3/4" 'classic' version. That's an important endorsement of the brand but since I know my guns are chambered for 3", I'm happy to go them one better. What I would like is a large enough supply of Black Magics to shoot a few practice rounds, since they will be packing a fair bit more recoil than I'm used to- but I'll have to find something similar with a 1&3/8 oz slug.
The printing on the shells themselves tells me they are rated "max. 1050 bar," but mainly being a low brass shooter these days that tells me little. I guess I'll keep them away from any older guns though.