First I have heard of it. I can say from the pictures that it isn't optimized for 12 Ga, but would probably do a little bit.
If you look at the brake testing done by me, by Fitty, and Vadim, and T&N.... You notice that nearly all the gas vectoring stuff happens in the first inch past the muzzle. Lots of gills close together does the most After that inch, everything is working with so little gas pressure that it may as well not be there.